Thrilling Wonder Stories
Vol. XV, No. 1
January 1940
pp 89-112

The Day of the Conquerors

Manly Wade Wellman

When space ships visit the stone age, prehistoric man wages a grim battle for the survival of the fittest on the brink of time's dawn



HOW do we know that this world cannot be visited from beyond space? How do we know that it has not happened already, far back in the darkest hour before history's dawn?

The Chinese tell of an antiquity when a giant and flaming dagger — the very pattern of a space ship — dropped from heaven and disgorged conquerors. The Greeks once worshipped a father of gods who hurled thunderbolts like javelins. There are a myriad of tales concerning enchanted strongholds, grotesque scoundrels who owned flying carpets and magic missiles, winged dragons and strangely powerful Jinni, and living monsters of stone, brass or iron.

But there is another side to the picture. There are the glad memories of heroes and princes who invaded these unvanquishable fortresses, outwitted these bizarre enemies, learned their deadly secrets and turned them against their wielders, with the result that man lives and prospers unthreatened today, free to make his own magic by science — science that has raised him to the throne ... and may yet, through misuse, hurl him into the pit.

Are these old legends real evidence? Did they begin with the day of dread when strangers came from a far world to settle and conquer this one, routing and almost destroying the human race in its youth — only to be checked and defeated by some paladin of daring wisdom whom we remember as Ulysses, St. George, or Jack the Giant Killer?




The Pioneers

THE ship that dropped down out of the sky was a gray-gleaming torpedo of metal, driven and guided by rocket blasts. The dozen who made up its crew were of the System's most advanced race, and themselves the leaders of that race. Their star-spanning craft bore witness to that leadership. They had sailed from their own world, the world that was fourth from the sun, the red planet. Now, with diminishing speed, they were approaching the planet that circled just to sunward of them.

The Martians were a frail-looking lot, a fact consistent with creatures of a light-gravity planet like theirs. Their bodies were narrow and soft, and their arms and legs of a sticklike length and slenderness. But their eyes were bright, and their craniums swelled impressively above their skull — thin faces with sharp, toothless mouths and long snipe noses. Their color was a dark red, like baked clay, and they wore close-fitting garments of metallic weave.

While the commander steered, the others gathered about a great telescopic vision-screen, studying the new green world to which they were voyaging.

"It has much water, three times as much as land," computed one. "Vegetation, large and small, covers everything. Life is rich here."

The others thrilled to the report. Their own planet was dying, a globe almost empty of air and water. Their hunger, their thirst, had driven them to hunt a new home for their race. Here might be that new home.

"Look for animals," spoke the commander from his steering levers.

They did so, questing here and there with the point of vision. At last, focusing by means of many dials and gauges, they could see one creature of the new planet. It was massive, mighty, its body covered with shaggy wool and supported upon four pillar-like limbs. Its mouth sprouted two great white teeth, and between those natural spears the nose sprouted into a wriggling arm or tentacle.

They looked upon the mammoth, which observers of today know only by its fossil bones. Interest and apprehension mingled in their minds. Ages before, the last wild creature had died on Mars, where every square foot of habitable ground, every breath of oxygen, every mouthful of food or water, was needed for the dominant race.

"A mighty beast," said the observers to each other. "Cunning, too — see how big its skull is, and how it uses that twisting member like a hand. It might be dangerous."

"Not to us," pronounced the commander arbitrarily. "We have the power to defeat it — and use it for our own purpose."

The group around the vision screen sought another viewpoint, focused upon another scene of life. Several beasts could be seen this time — a lithe, tawny mother at the dark door of, a cavern, cradling two cubs between her forepaws and licking them affectionately, while a male, thickly maned on throat and shoulders, stood guard over them. It was a family of cave-lions such as once roamed young Earth, carnivora beside which modern lions would seem small and timid,

"There is real ferocity," commented one watcher. "See how Nature has made that thing of muscles and fangs and claws. It could strike as swiftly as lightning, almost — and as fatally."

A natural machine of combat," agreed his companions.

"Yet our artificial machines have outdone nature," spoke up the leader drily. "Do not fear any blood-drinking brutes. We can do with them what we wish."

THEY turned their peering view-mechanism elsewhere, studying birds that flew. This latter fact reassured them that their own flying machines could travel in this heavy atmosphere. They noted monkeys playing among bright green foliage, herds of antelope, a lumbering cave-bear, a giant snake.

At last they came to the landfall, in the center of a gently cupped green valley. Leaving his controls, the commander moved to a gauge and quickly checked its figures.

"The air is good, full of oxygen," he reported. "Open the hatch, and we will emerge."

No sooner had they quit the zone of the ship's artificial gravity than they gasped and staggered — the new world exerted almost thrice the pull they had known at home. But the more bracing, oxygen-rich air helped them to make the required effort, to overcome this unaccustomed environmental feature.

They proceeded routinely to make a fortress. One Martian, with an atomic blast-control, walked heavily in a wide circle around the ship, turning the nozzle of his mechanism against the ground. It churned up the earth into a great red-brown bank, which he shaped by skilful manipulation of the blast-control, and drew into existence as swiftly as he walked. Displacement of atoms, within planned limits, made such earth-sculptoring quick and sure.

Meanwhile others, exerting their stringy muscles against the threefold gravity, were joining together the parts of a flying machine, with a closed central gondola in which a pilot could sit forward and two observers aft. It had planes jutting to either side, a rocket engine for propulsion, and a destroying flame-ray at the front.

Three were told to board the machine and go off exploring. The others worked to finish the earthen rampart, and to raise shelters inside it. The shelters took longer and finer work with the blast-control, but the commander would not rest until they were finished.

"From the looks oŁ this sky, and the samples of the atmosphere, we may have storms," he pointed out. "They could do us more harm than any strange beast, or combination of beasts, on this planet."

He had picked up a length of stick, to help support his heaviness in the new gravity. He walked to where one of the adventurers, the youngest, was bringing out and assembling with a wrench certain strange bits of machinery. As this work progressed, it took a form like that of the Martians but heavier — a body, two legs, two arms, a cylindrical head that bore a foggy-lensed lamp instead of a face. It was a robot.

"Vwil," said the commander, "you are meditative."

The young Martian addressed as Vwil lubricated the joints of the completely assembled robot, then pressed a switch in its body. The metal image came to life, moving stiffly but surely, like a Martian in armor. Vwil handed it the wrench and pointed silently to the interior of the space-ship. It moved away understandingly, brought out armfuls of new parts, and began building them into other robots.

MEANWHILE, Vwil faced his chief. His features, though thin, were fine-cut and responsive, and lacked the hard determination of the other's.

"I was wondering," he said, "if there were not creatures like us on this planet."

The commander's harsh mouth screwed into something like a smile, and he shook his head.

"No, Vwil. Nothing so close to your romantic dreams. We have observed no cities, no machines —"

"Are cities and machines everything?" broke in Vwil, not so courteously as he should. "I see this world as a great garden, full of good things, as our own was in the beginning. Perhaps there are fellow-beings, not as wise as we, but good and kindly —"

The commander interrupted. "Sentimentality is not good, Vwil. We outmoded it many generations back, and it does not fit your otherwise fine scientific character. Least of all is their place for it here. We are overcrowded and underfed at home — we are here to explore and establish a colony, not to dream."

He paused a moment, musing.

"Yet you give me a thought. There may be animals here who approximate us — walking upright on two legs, with deft forelimbs like hands, and a considerable brain-case at the top. If so, they may prove most useful." He scrutinized the robot, which was working on yet another replica of itself. "More useful even than those things of metal and motor."

"You would enslave such unhappy beings?" suggested Vwil.

The other sneered.

"Do not torture yourself with dreams of how unscrupulous I am, until we know that there is such an animal — a two-legged entity, similar to us in shape, and of good potential intelligence."

Vwil patently wished there would be nothing of the sort, for the commander's attitude was of one who planned ruthless miracles.

The two did not know it, but even as they conversed, a. tall biped, shaped like the Martians but along more powerful lines, was skirting a waterside not far beyond their horizon.



The Defier of the Gods

HE was blue-eyed, that specimen, and his shaggy hair was black. Despite his great length of limb and body, he was broad only where it counted most, in shoulders and hands. The bright sun he worshipped as a god had tanned all of him save where buckskin girdled his loins and sandals shod his feet. His face — broad-browed, square-jawed, straight-nosed, ready to smile — was clean of beard, as befitted a young bachelor of his people. His name was Naku, and he belonged to the Flint Folk — the tribe of hunters and fishers who dwelt in a village of wattle-and-daub huts under a lakeside bluff, and chipped beautiful tools and weapons from stone.

His name meant Lone Hunt. It signified that from boyhood he had preferred to play and adventure by himself rather than with the shrill naked rabble of other children. Now, as a young man, he still liked solitude. Neither sullen nor timid, he was yet reserved and meditative.

He might have become a priest, but the Flint Folk had begun to turn away from the sun-worship to which they were bred, and Naku scorned the new cult of the Thunderer — the more so because two years before, that surly deity had sent a storm and sunk the canoe in which his father and mother had been paddling on the lake.

Naku was a mighty stalker of game and shooter of arrows, the swiftest runner and the fourth best wrestler in the village. Secretly he hated the Thunderer for killing his parents, and often dreamed of vengeance. Just now, following a deer-track along the lake's margin, he reviewed in his mind all he had heard of the angry, bloodthirsty Thunderer. The fat lame priest, Ipsar, said it was like a great eagle, but larger and more deadly. Only Ipsar had seen it, and Ipsar preached terrifyingly about its powers and anger. But he, Naku, would never worship — might even find a way to make war against—

What Was That Shadow That Fell Upon Him?

Even as the great bulk blotted the sun from him, Naku dived sidewise from the beach into a reedy thicket, like a frog into water. His hunter's instinct told him that the thing lived, flew like a bird — but was far bigger than any bird or beast he had known. From his place of hiding he glanced up, at great motionless wings, a gleaming body, and a quivering tail-like stream of smoke. The creature had a voice, too, a rhythmic rumble like the deep song of a locust. This much Naku noticed before the thing whipped out of sight beyond the horizon, as swiftly as it had come.

"Whoo!" said Naku, and came into the open. He had seen the Thunderer, heard it. Old Ipsar had foretold something of that sort for unbelievers — the fierce god would appear and strike them dead. Musing thus, Naku felt relieved. It had come for him, but had failed to strike or seize him. His dash to cover must have baffled it.

A new doubt rose. If the Thunderer could fail, it might not be a god after all. No, only a dangerous monster, like the dragons of old, of which grandsires told children, the beasts that had fought and frightened the ancestors of the Flint Folk.

Such a thing would be fought against, perhaps killed. Naku looked to the arrows in his otter-skin quiver. He set one to his bowstring and moved forward, warily but steadily. Forgetting the deer he hunted, he left the lake shore and struck through the forest in the direction taken by the flying thing. He moved swiftly, cunningly, between trunks of maple, beech and oak. After trotting many bow-shots of distance, he came to the edge oŁ the woods, at the brow of a hill. Beyond was a valley he knew, shaped like one of the clay saucers which the Flint Folk knew how to model. From behind a spray of willow shoots, Naku peered out.

HE frowned. Did he know this saucer-valley, after all? Surely it had been only a green round dip, with a pond at bottom. Whence had come those strange lumps and ridges of red-brown stuff, like clay gigantically moulded and baked? It was — yes it was a village, a fortress, made here of earthy materials. Within an uneven curved compass of walls or dikes, rose the round and conical tops of buildings. And lights flashed from the hidden inner court of the enclosure, and smokes ascended, smokes colored brown, slate-blue, blood-red, black. Naku sniffed. Those smokes were of unpleasant pungency.

Meanwhile, just outside the walls, the great flying mechanism that Naku fancied was the Thunderer had come to rest.

He peered and appraised. The big bird must live here, and indeed it was doing a most domestic thing — laying eggs. He saw objects issue from within it, two of them. But not eggs. These moved, they were alive. Baby birds? No. Animals? None that Naku knew. Men? Well, they might be men.

They were shaped something like himself, but were gaunt, scrawny, like rude figures scratched on a board or bone with single marks for limbs. Their heads were long and puffy, like very ripe gourds, and had no hair. Their skins were colored a deeper, warmer red than the walls they approached, and their eyes were large and round and green, with snipe-noses and thin mouths.

Stepping into the open, he aimed his arrow. With a sudden skilful flexing of all the proper muscles, he drew that arrow to the head and released it. The flint-tipped shaft yelped in air, flew across the valley like a little flying serpent, and struck its mark fair in the gleaming flank.

The monster seemed to speak, with a voice such as Lone Hunt had never heard — like the ringing of a water-drop in a pool, but unthinkably louder. Naku's people knew nothing of metal. Naku was having new experiences indeed. He felt a thrill of exultation for the echoing ring of the plates must be the cry of a wounded creature.

Setting a new arrow to string, he watched. A great hole had appeared in the forward part of the body, and something moved there. Lone Hunt sped his second arrow straight for and into that hole, and the movement checked abruptly. A new sound drifted forth — a wailing sigh, as from a severed throat. Lone Hunt grinned. He was conquering the Thunderer.

Except for those heads, and their spidery hands, the creatures were sheathed in tight, shiny clothing.

As Naku watched, the new mysteries moved toward the red-brown wall. A round opening appeared, like a cave-mouth from which a stone is rolled away. They went in, and the hole closed. For the first time, a man of Earth had seen an automatic door-panel in use. Only the giant flying thing, grounded and silent, remained outside.

All these things were strange, without precedent in Naku's experience, but he did not let his wonder paralyze him.

"It is more and more like the strange tales of the grandfathers," he told himself, "tales of beasts that speak, of dead warriors' ghosts that come at night to foretell the future, and other things. This is like such a story," Naku decided sagely, "but, instead of hearing it told, I see it happening. Men who see such things become great and strong if they can profit by what they see."

Thus heartened by his own reasoning, he studied the situation cagily.

"The Thunderer has built a home here," he concluded. "He is an enemy — and, I think, not a god. I shall kill him."

BUT, at the new cry, the hole reappeared in the wall. Out scrambled two of the twig-thin creatures, perhaps the same pair that he had seen before. The hurried to the forward orifice, and hauled into view a companion. That companion lay still and limp, and from its high skull jutted Naku's arrow. The two living things examined the corpse and the shaft. Even at that distance, they seemed agitated.

Naku flourished his arms.

"Hai! Hai!" he yelled defiantly. "I killed him, I — I — I! The Thunderer blew storm and drowned my father and mother. I, Naku, take vengeance."

The creatures turned toward him. One was handling something that gleamed and twinkled, a short rod the length of Naku's forearm and as thick as his two fingers. From this bright object suddenly belched a greater brightness — a flash of lightning, surely, that leaped clear across the intervening space at Naku.

But he had expected some sort of assault, a charge or a hurled missile. He fell flat on his face, and just behind and above him he heard a crackle of fire. The trees kindled to that beam of light, which cut through the space just occupied by Naku's own torso.

The hunter cursed, scrambled well to one side, rose behind a bit of scrub and launched yet a third arrow. It struck the skinny chest of the ray-wielder, and he collapsed across the body of his dead friend. The light switched off. The surviving stranger bundled himself frantically into the forward opening of the Thunderer, and the shiny shell closed up. Naku felt himself master of the field — the Thunderer struck dead, and two of its mysterious children—

Wait! The Thunderer was not dead! It rose from the ground, swooped toward him! Naku did not fear greatly. He thought that he could spring into the woods, where that immense soaring mass could hardly follow him.

But the Thunderer, too, wielded the lightning, it flung a burning white flash at him. Naku, retreating among the trees, felt them spring into fire around him. He himself was saved because he shrank behind a big gnarled oak — the other side of it blazed up in the moment he stayed. Springing sidewise, he ran and ran. Chance brought him to a creek which flowed lakeward. His mind struck the saving equation for him — the enemy fought with fire, and he, Naku, would protect himself with water.

In he splashed, and none too soon. He swam down to the muddy bottom, and heard dully a great swishing gasp — the ray of hot light was drawn along the surface of the water, turning it to steam. The creek heated unpleasantly in that brief moment before the ray left it. Naku swam as far as he could on the bed of the stream, came to a wide pool, and cautiously peeped out.

He could see the flying monster high up, hovering in place and probing the forest with its ray, as a boy stirs grass with a stick to find a hiding lizard. Flames darted above the treetops everywhere, and this was no place for a man whose bow had been ruined by water, anyway. Naku swam swiftly but silently with the current, came to shore a long bow-shot ahead, and ran back the way he had come.

He paused once more on the shore of the lake, near the spot where he had first seen the Thunderer in the sky. Glancing back, he found that his enemy had flown away, but the forest roared with the fire it had kindled to destroy him.

Naku, swiftest racer of his tribe, outdid himself in the flight for home.

WHEN the flying machine returned to the Martian camp, there was a grim council.

"Two killed out of twelve, and by one primitive animal with the crudest weapons," summed up the commander bleakly. "And he got away." His gaunt, hard features seemed turned to carved wood. "I am not pleased."

"We did not know of attack," protested the one who had flown after the raider. "Anyway, I set the forest afire. He will not survive that"

"I am afraid that he has already escaped, and warned others," replied the commander. Vwil spoke up. His face was calmer, gentler, than the others. "Perhaps, if he understood that we meant friendship —" he began. "Do not speak for everyone, Vwil," snubbed the commander. "This is war. If the creature escaped, he will bring others of his kind. We will prepare for that."

He turned toward the knot of new-assembled robots, fixing his eyes upon them. He did not speak or gesture, but their delicate receiving mechanisms understood and obeyed his thought-impulses — they came toward him, a full score of silent metal men, each with a glowing face-lamp that gave off pulsations of white light. At his unspoken will they moved quickly to the space-ship in the center of the stockade, and entered. They emerged with a variety of weapons.

"I still hope —" began Vwil timidly.

"It makes no difference what you hope," the commander snapped. "If we are to be safe here, we must be masters. These savages are intelligent, brave, warlike. We must teach them a lesson, in terms they understand."

The others nodded agreement — all save Vwil. He was deep in thought.




AT home, on the sandy, hut-studded level between lake and bluff, Naku was talking more loudly and passionately than any had ever heard him. First he thrust himself upon Rrau, the war chief, and began to fling earnest words at him. Others, curious, came around, and what they heard caused them to beckon still others. As the men of the tribe poured from their huts and thickened into a big audience, Naku ceased his talking to Rrau alone. A great log lay at hand, and he sprang upon it, raising his voice so that all might hear.

"Men of the Flint!" he addressed them. "I come from seeing marvels. The Thunderer nests near here, it hurls fire upon the forest and threatens to kill us all! With it come strange creatures, like ugly dreams of skinny men, who attack good warriors, but who can themselves be killed!" He paused, and an amazed murmur went up. "I have seen the monster, and have shot arrows at the men-things it spawns — I have killed two!"

The murmur died. All gazed aghast at the comrade who had dared face and defy the Thunderer. Those nearest him moved away, and Naku saw and laughed.

"You are afraid that I will be struck with the Thunderer's lightnings? You do not want to share that death? But I was threatened and escaped. It hurled fire — and missed! Men of the Flint, my friends and brothers, this Thunderer is no god. He is only a dangerous and evil monster, and must be killed."

He glanced shrewdly around. Here and there he saw a bright face among the dark ones, a face suddenly touched with hope. Others of the Flint Folk disliked the Thunderer worship, yearned like himself for the return of service to the warm, beneficent Shining One, the sun. One such face was that of Rrau, the war chief. If the brave and popular leader should join his voice to Naku's ... But here came hobbling a fat, excited figure — Ipsar, the priest who led the new cult of the Thunderer.

Ipsar was the only man of the village whose life was so soft and easy that he could grow fleshy. He wore a great red beard, like the lightning itself, braided into two plaits. His body was clad in a deerskin skirt and jerkin, and painted over with mystic jagged symbols. Around his neck were looped great chains of bright pebbles and shells, and other chains bound his fat arms and legs.

Upon his head rested a strange cap or helmet, a curved and spiraled thing that gave off faint flashes of rainbow-tinted brilliance. Ages before, it had been the shell of a nautilus-like sea creature and had become a fossil, turning to stone. Found — by some ocean-side loiterer, it had been prized, and in some way — a tedious succession of tradings, journeyings, thefts, war-plunderings — it had come the far distance from the sea, through the hands of a dozen peoples, into possession of the Flint Folk. Unique, glorious and full of mystery, it was the sacred head-dress of the priest. Some of the inner spirals and partitions had been cut away, so that the thing fitted Ipsar's head snugly.

"Liar!" screamed the red-bearded man at Naku. "You speak sacrilege. If the Thunderer hurled fire at you —"

"I say that fire has been hurled. Look." The young man pointed to where, in the forest far along the lake's margin, rose brilliant banners of flame and clouds of smoke. "But it missed me. The Thunderer, I say again, is no god. If he is, let him strike me!"

EVERYONE waited. Naku shook his fist into the sky.

"I defy the Thunderer, I challenge him to fight me. See, nothing happens! If it hears, it is afraid!"

He gazed at the press of men around him, and farther at the timid, shifting fringe of women and children. He felt that his people half believed. Then another figure sprang to the log at his side. It was Rrau, as lean and gray and fierce as a wolf. The chief glared, and his beard bristled.

"Naku speaks the truth!" he trumpeted like a mad mammoth. "I have never believed in the Thunderer, but when others of you turned after Ipsar's preachings I kept still. I am a man of war, not of words, and I thought to let the matter be proven before I took one side or the other. I say now, that it is proven!" He turned to Naku. "This man I know of old, and his father before him. He does not lie. What he says has happened. If he defies the Thunderer, so do I!"

At such an uncompromising statement from so important a figure in the community, a ragged cheer went up. Even those who had worshipped the Thunderer at Ipsar's cunning behest, did so through fear — fear has always won more respect and service than beneficence. The old cult of the Shining One had been less exciting, but more kindly. If the fierce new deity could be overthrown, the Flint Folk would be thankfully pleased. One or two of the fiercest set up a shout.

"War! War!"

"Fools!" snarled Ipsar, but his voice was drowned in the swelling outcry. Rrau sprang down to earth and spoke to a brawny fellow near him.

"Seize that priest and hold him prisoner. His words, not Naku's, are lies. We will go and see this Thunderer. If he seeks to do us harm — well, our arrows of flint are sure, our axes and spears of stone are sharp."

But Ipsar went skipping and hirpling away, swift for all his infirmity. He looked funny, and the simple Flint Folk laughed. That laughter spelt the sudden end of his influence, of his soft living, and of the power of fear he wielded. Almost at once he was forgotten. Even the man to whom Rrau had spoken turned from pursuit, anxious to be one of the adventurers who would march against the Thunderer.

Rrau counted the fighting men present. There were a good sixty, more than two-thirds of the able-bodied men of his tribe. He weighed the number against what Naku had told him of the Thunderer's fortress.

"These are enough," he pronounced. "There must be more of us than of those Thunder Folk, and Naku says that they are weak and thin to the seeming. Also, we will sneak upon them without their knowledge. When the others return from hunting, let them stay here and keep watch." He lifted his voice to bellow orders: "All warriors, go to your huts, take your best weapons! Follow me! Naku, lead the way!"

More cheering and enthusiastic hubbub. The party formed quickly, a column of twos, with Rrau and Naku walking together at the head. The women exhorted their males shrilly, and the men laughed back that they would return with the wing-feathers of the deposed god with which to sweep the hearths of their huts. At Rrau's gesture, the column moved out.

THE noise and laughter died out quickly, but not the determination. Naku led his companions in a wide curve to avoid the section of forest that still smouldered, and Rrau kept watchful scouts far to right and left of the main body. At length the expedition came to the trees at the brink of the cup-like valley. Rrau and Naku, moving cautiously forward, peered out and down.

"The fortress looks larger than you described it," said Rrau at once.

"It has grown since I was here," replied Naku, wondering how, in less than half a day, the strange Thunder Folk had made great curving redoubts that swelled their lair to almost twice its original size. He and Rrau studied the light reflections and rising threads of smoke that showed inside, speculating vainly on what they might be. They had no conception of furnaces, refineries or forges.

There was a busy sound in the air, a blend of clanking metal, churning wheels, dragging of weights. The Thunder Folk — those invaders from a far world — were tightening their grip upon the empire they hoped to conquer.

"Look!" said Naku suddenly.

From another part of the forest's edge, beyond the section which had burned, darted a human figure. It was heavy-set, and ran unsteadily down the slope toward the walled spaces in the bottom. The sunlight glowed upon a flying red beard. Ipsar, the priest, was hurrying toward the lair of his god, the Thunderer.

Naku fitted arrow to bow, but the priest was too far away and moving too fast for a sure shot.

"He goes to warn the monster," he muttered to Rrau. "He is afraid for it. He knows that it is not all-powerful."

"That is well," responded the chief. "We shall destroy him along with his Thunderer."

At that moment, the circular door in the rampart opened. Something poked itself out — a gleaming something, at which all the hidden Flint Folk stared. It drew itself into view, a jointed object that moved and postured, and seemed to have a form grotesquely human.

"Is that one of the Thunder Folk?" the chief asked Naku.

"No, it is something new. It looks stronger, and it has no face — only that round light at the front of its head."

The robot moved to meet Ipsar. A second robot emerged. Behind them lurked one of the stick-limbed Martians, a baton-like ray thrower in his red hands.

Ipsar sensed danger, and howled for mercy, throwing up his fat arms. The robots moved to either side of him, towering high above his head. They clutched his shoulders with the lobster-claw appendages that served them for hands. Ipsar winced, but when they drew him toward the door he went willingly enough.

"Let us begin the fight," said Rrau, and Naku, stepping into the open, drew and aimed his arrow.

He intended it for Ipsar, who patently meant to betray his people to the enemy, but just then one of the metal giants interposed its cylindrical body, and against it Naku sped his shaft. True to the mark sang his shaft, and bounced away. Loud rang the impact, the same sort of vibrating noise that Naku had evoked when first he shot at the flying machine he called the Thunderer.

BUT the robot was not hurt. It only turned itself in the direction from which the arrow had come, seeming to glare upward at the forest-edge with its foggy light that was like a single eye in its blank, hard head. The other dragged Ipsar into the stronghold.

"Shoot, all of you!" growled Rrau at the other men.

They, too, sprang into the open, a skirmish line of ready warriors. At almost the same breath of time, their arrows were launched, a sudden storm of flint, converging on that dull-shining figure that stopped to face them.

The air rang with the multiple impact, but the arrows glanced away like hail from the side of a cliff. The thing did not even reel. Instead, it took a slow step toward them.

Another robot came forth from the fortress, and another and another. They ranged themselves besides the first. Then more appeared, a dozen, twenty. Some carried the metal rods that threw flaming rays. Others had long blades, with keen edges. One or two bore sheafs of shackles.

Again a volley of arrows, straight to the targets, but absolutely ineffectual.

"They have shields of some kind — or magic," muttered Rrau. Again he raised his voice: "Do not fear, men of the Flint! Take axes and spears — they are fewer than we — charge at them!"

He himself sprang forward and led the rush, his mighty axe whirling overhead — a keen, heavy blade of stone set in a tough shaft of dark wood. Rrau could strike heavily and accurately enough to split the skull of a bison, and if these shining things were men — even men with some sort of armor, like a tortoise or crocodile — he would show them who was master. Inspired by his example, the other Flint Folk whooped and charged.

The robots did not move, either to retreat or to resist. They only stood in a row, each poising a weapon. It was not until Rrau, twenty paces in advance of his charging tribesmen, was almost upon them that a robot stepped forth, lifting the ray-rod in its claw-like hands.


Rrau thundered his war-cry, sprang high into the air, and for the moment was on a level with his tall opponent., With both sinewy arms he swung his axe, in a great whistling arc, full upon the top of the metal lump that did duty for the robot's head.

Thunk! It drove home, a blow that would have severed a tree-trunk or smashed a granite boulder — but the robot barely buckled. The flint edge crumbled, the metal head wagged, and only a slight dent showed.

Then came the response. The machine-man leveled the weapon it held. Forth gushed a streak of white fire. Rrau, chief and champion of his people, at whose name enemies trembled and sought to hide, was suddenly nothing — nothing but a fluff of smoke, a settling scatter oŁ ashes. He had been rayed out of existence.

As if by signal, the other robots came into the fight. With a knowing sweep of their rays, they blasted and burned the oncoming horde of fighting men. Warriors were blasted to smoky atoms, before they could cry out with pain. The survivors paused, wavering. And then the robots moved upon them with deliberate intent, swinging their blades and plying their rays.

The Flint Folk knew fear, a fear of which no mortal need be ashamed. They turned and ran, all save one — Naku, who had run abreast of Rrau but at a distance, and was now cut off by the counter-charge of the robots. The machine-men had fixed their attention on the main body and seemed to ignore this isolated figure, but he could not reach the shelter of the trees.

Turning, he fled along the curve of the great wall. One robot was aware of the sudden movement. It detached itself from the detail and clanked in swift pursuit.

WITHIN the Martian ramparts, the commander was grimly jubilant.

"See, they run!" he cried, gazing into the vision-screen that had been set up in his hut-like shelter at the center of the enclosure, just beside the parked space-ship. "They cannot hurt our robots, and cannot stand against our weapons. We have completely wiped out those who were too slow or too stupid to flee. The extermination of the survivors will be easy."

"Could they not be spared?" offered Vwil, and his superior made a gesture of disgust. "Sentiment again — it has no place in science or conquest. Yet the study of captives of this race might be interesting. The single specimen who came to us of his own accord is, I think, unusual. For one thing, his brain refuses to receive the command-impulses of my own mind, as have those of the other animals we have snared."

He jerked his high-skulled head toward a quarter of the settlement where, in a row of pens, were imprisoned some antelopes, two bison, and three disconsolate mammoths, as well as other beasts.

"If he was controllable, he might become a useful slave, a supplement to these expensive and limited robots."

The two gazed to where sat the pudgy form of Ipsar, the renegade priest. He was shackled and disconsolate, his red beard out of its plaits, and a robot stood near to guard him. On his head still rested the fossil nautilus-shell that did duty for ceremonial helmet. None of the Martians had seen fit to remove it.

"His face looks evil," observed Vwil. "The fact that he came submissively to us, while the others fought, shows that he is a traitor to his own kind. Therefore —"

"Therefore," the commander finished for him, "he may help us with our conquest. But your arguments have given me a new idea, Vwil. Not long before the battle, I sent a flying detail to capture some more of these bipeds. We may not kill off the race. Not all of it, anyway."




NAKU the fleet of foot, sped around a curve of the wall, out of sight of both his routed companions and the robots. There he paused, panted and listened.

Clunk, clank, clank, came a rhythmic, muffled ring. Two feet — feet of that strange gleaming stuff that vibrated when struck. One of the strange monsters was pursuing him.

For a moment Naku felt a grip of unreasoning panic, then his wits came to his rescue. One monster pursued him, only one. Perhaps the others knew nothing of him. If he broke into the open, he would be sighted and overhauled. But just now the odds were even, and perhaps, with luck—

He pressed his body close against the wall, and in his right hand poised a spear with a flint tip.

The robot came into view along his back trail, and it held in one claw a curved blade, in the other a pair of shackles joined by a linked chain. Death or capture for Naku! And its round glowing face-lamp turned upon him. Abruptly it bore down.

Naku threw his spear, instantly and with deadly accuracy, full at that disc of light. It was a direct hit, with all of the rugged strength of his muscles behind it. And, as he had been inspired to guess, that disc was the one vulnerable spot.

The pane of clouded glass, that to Naku looked like ice, splintered away. The flint head of the spear crashed into the lighting mechanism behind, obliterated it and lodged among the ruins. The robot stopped its advance, staggered, and dropped the shackle. Clumsily it clawed away the shaft, then stood, baffled and disconsolate, its arms out-flung as though to grope. It acted like a man suddenly gone blind.

"Ho, you are wounded!" Naku taunted it. "I struck you — I, Naku, the enemy of your father, the Thunderer."

But it could still hear, or at least it had some sense that approximated hearing. At the sound of his bantering voice, it groped quickly toward him. If those great toothed pincers should close upon his body, he would be lost. He had no weapon left save the flaked poniard at his girdle, and he did not want to come close enough to use that. Therefore he retreated before it, and it heard the soft shuffle of his sandals. It tried again to close in. Naku, still fearful of being caught in the open, stayed close to the wall, falling back and watching his blinded pursuer.

He saw that its limb-joints and the juncture of its neck at the top of the body cylinder gleamed with an oily blackness. Naku did not understand mechanical lubrication, but he knew about the use of bear-fat, dried out and used to dress wounds or sunburn. Once or twice, in wrestling games, certain of his fellows had craftily greased themselves to foil a grip. Naku, still breaking ground before the uncanny metal thing's blundering pursuit, began to put two and two together.

The black oil at the joints was to make for easy, slippery motion. If it were clogged, the thing might be overcome. He remembered a counter-stratagem he had once played on an unethically oiled wrestler. Stooping quickly, he clutched both big hands full of gritty earth. Then he straightened up and stood his ground.

"Hai!" he addressed his adversary. "Come close now, if you dare!"

IT CHARGED at the sound of his voice. It towered above him by the height of his own head, and seemed of tremendous weight. Naku pluckily met its rush, however, and with desperate precision hurled his two handfuls of grit, one upon each shoulder joint. Then he sprang aside.

The effect was all that he could wish. The monster blundered past him, but the lubrication of the metal shoulders was clogged at once, and the arms could barely move. They made harsh rattling sounds, and seemed to lose control of themselves. Standing still, the robot cocked his grotesque blind head, as though to listen for his movement.

"Here I am!" shouted Naku beside it, and again sprang aside. As it turned and stepped in the direction of his voice, he placed both his hands against its flank and gave a mighty push. It stumbled, crashed hard against the wall, lost balance and fell. The blade it held went spinning away.

At once Naku sprang in, scooping and hurling earth with the savage swiftness of a fire-fighter. He heaped grit upon the joints of hips, knees, elbows, neck. The metal body ceased its struggles, whirred and grated inside, slackened off. Naku felt a high thrill of victory. He stepped close to examine his fallen foeman. Was it dead, or only shamming?

At that moment, a whirr sounded from the heavens, and something dropped down — the flying thing, the Thunderer. Naku dropped his own body, like one stricken, and shielded himself behind the bulk of the robot, peeping warily over its torso with one eye.

The machine settled itself, before the section where the door would be, but far enough out to be within the line of his vision, and out came two of the scrawny men, with a robot. The robot held the end of a chain to which, like a dog on a tether, was fastened a fourth figure.

A human being, like Naku himself — no, not like him. It was a young woman, a girl. Naku lifted his head by the breadth of a finger, to see more clearly. She was a prisoner, it was plain to see, for her wrists were securely shackled. He could not tell from what tribe she came, but guessed that it lay well to the north. She had the blonde hair of the northerners, lots of it in disordered clouds about her face. A handsome thing she was, too — slender in her brief tunic and kirtle of deerskin, straight and proud and shapely.

Her captors led her out of sight.

Naku pondered this new thing he had observed. Apparently the Thunder Folk did not mean to kill indiscriminately, after all. The girt, though securely bound and guarded, did not appear harmed in the least. And the heavy, shiny hulk he had conquered with his hurled heaps of dirt had carried not only a weapon but a shackle with which to bind him. Naku smiled to himself yet again, in self-applause at his new triumph.

"Three I have overcome," he thought. "One died of an arrow in the very heart of the Thunderer — a second before the opening to their lair — and now this one, a strange giant and the biggest of the three. There will be a fourth victim, and a fifth. I will conquer them all. I, Lone Hunt, am stronger and greater than these Thunder People!"

It was a proud thought and, even in those far-off young days, pride often went before a fall.

IN THE midst of his musings, Naku was aware that he was being approached stealthily from behind. He sprang up and spun around his hand to his dagger-hilt.

Two creatures had evidently issued from another door, farther along the wall, and now stole upon him — a big gleaming robot, and a gaunt, heavy-trudging Martian with a dark red face. The Martian, in advance of his metal servitor, leveled a small shining rod that had a round opening in the end pointing toward Naku.

The simple warrior had seen the rays in action all too closely, and he knew what such a device might be. He could neither fight nor fly. All that was left to him was to die bravely, he felt, and that he determined to do.

"Throw your fire at me, coward," he challenged. "I have killed more than one of your brothers. I am not afraid to die. I laugh at you."

And he did so, merrily. The skull-lean, snipe-nosed face of the Martian smiled in answer, neither fiercely nor mockingly. The tube, pointing at Naku, gestured at him as though to bid him turn and walk.

Naku shook his head.

"Not I," he demurred, "If you want to burn me, do it now — not sneakingly from behind." And he planted his feet, glaring at what he felt certain was his destruction.

The creature sighed as though in regret, and touched a little projection on the rod. Fire gushed forth — not white, but pale blue. It enveloped Naku like a splash of water. He felt no pain, only languor. His senses were slipping. His knees sagged, his eyes closed, and he felt himself gently collapse.

THE Martian commander came from his headquarters just as Vwil entered the fortress. Behind Vwil clumped a robot, carrying in its arms a limp human form.

"Did you venture out?" said the commander.

"Yes. I was at the power-caster, and the gauges showed that one receiving set had ceased to take energy. I guessed that it must be a damaged robot, and reconnoitered. I found that this native had overcome and wrecked one of the robots. I disabled him with the sleep-ray —"

"Why did you not kill him, since he had harmed us?" broke in the other. "Oh, but I forgot that laughable softness of your spirit. Well, perhaps you did rightly. If he was adroit enough to defeat a robot, he may have a nervous system complex and sensitive — worth my experimentation. Have him put in the new pen with those others of his kind."



Conference with the Invaders

WHEN Naku awoke, he felt sunshine in his face, earth against his sprawling back, and a pillow, soft but firm, under his head. He opened his eyes, and looked into a most admirable face.

It was a woman's face — young, oval, firm-jawed, straight-nosed, blue-eyed. It was flanked by two braids of sun-colored hair that caught gleaming lights. A low voice questioned him anxiously.

"Are you badly hurt?"

Naku sat up, flexed his arms and stirred his legs.

"No," he decided. "I remember being struck down by blue fire. What has happened?" He turned to face the girl on whose lap he had been pillowed. "Who are you?" "My name is Arla. We are prisoners of these — I do not know what they are called, but they are very evil."

Ordinarily Naku, reserved from boyhood, would be wary and shy before a stranger girl, but this one had done her best to help him. He studied her closely, and remembered seeing her before — this was the captive who had been brought in the Thunderer, the flying thing. He smiled at her thankfully, and looked around.

They were in a cage, with a flat roof of hard-packed earth, such as the Martians know how to fashion with their control-devices, and walled with perpendicular bars of metal. Part of these bars made up a door, fastened with a complicated lock. Against the door, at the far end of the enclosure, sat Ipsar, still dressed in his garish garments of priesthood, but very rumpled and disconsolate. He met Naku's eyes, and growled:

"Be careful of that woman. She is a wasp."

"He says that because he felt my sting," Arla informed Naku. "I do not seek the caresses of fat strangers."

Naku, studying the priest, saw that one of his eyes was badly bruised, as from the impact of hard little knuckles, and grinned. Then his face went serious again.

"We three must be friends and help each other," he pronounced. "These Thunder Folk have killed many men of my people, and hold us captive. How can we get away from them?"

"We cannot get away," said Ipsar sourly. "The power of the Thunderer is too great. He flies, he strikes fire—"

Arla shrugged her pretty shoulders in contempt.

"I know about this thing he calls the Thunderer," she said. "It is no living bird, but a thing made and operated by men — or, rather, by these manlike devils you call the Thunder Folk. The thing is hollow inside, with doors, like a hut; but it is a hut that can fly."

"Can it be?" cried Naku, trying to comprehend.

"I have been inside, and have seen. One of the Thunder Folk sits among strange sticks and round whirling things, and by handling them makes it go fast or slow, up or down. It swooped upon me as I fetched water just outside our village to the north. I was made stupid by fear, and those inside seized me. I rode in the thing with them, and used my eyes."

NAKU digested this.

"How can a thing not alive be made to fly or move otherwise?" he demanded.

"Can not a man make an arrow fly in the direction he chooses, by the power of his bow and the aim of his eye?" returned Arla. "Can a noose of rope not draw tight, as though it were a hand? This flying thing operates in the same way, but more wonderfully."

The idea sank in, and Naku had a contribution of his own.

"The big, strong things that walk and fight, and seem to be men," he said, "the ones made of shiny hard stuff, and bear round foggy lights in their faces — they, too, must be strange fashionings. They are tools!"

"Even if so," argued Ipsar, "they are too deep a matter for us to understand. We must submit to the power of the Thunderer."

"The Thunderer, I say, is only a tool, a utensil that flies at the will of its owner," snapped Arla.

I think that she speaks truth," seconded Naku: "If it is a deep matter to handle or to operate it, maybe I still can learn, as a child learns to shoot with the bow or to make a noose."

The argument was interrupted by a clatter at the door behind Ipsar. Startled, the priest slid sidewise, and the section of bars swung back. There stood a Martian, supporting himself on a stick against Earth's sore pull of gravity. He beckoned to Naku with a hand that, though claw-thin, was plainly human, of flesh and bone.

"He wants you," spoke Ipsar. "Obey him — go."

Naku shook his head, and felt for his dagger. It had been taken from him.

"I will not obey," he said sturdily. To the Martian he snarled: "Come in and try to take me. I will break your scrawny back across my knee."

The Martian only smiled — Naku saw that this was the one who had overwhelmed him with the blue ray. Then the Martian turned and fixed his brilliant green eyes upon an attendant robot. He did not speak nor make a gesture, but the metal monster understood. It entered the cage with heavy steps, seized Naku and carried him out, struggling and kicking like a naughty child.

As it bore him away, his angry eyes had a glimpse of the interior of the fortified place, and it was as if he were in another world. The ground underfoot was paved in geometric design. Strange shelters of tile and metal stood here and there with, in the center of them, the great gray-gleaming fish that was the space ship.

Here and there stood or sat Martians, but none of them moved more than necessary against the drag of Earth. Most of the work — smelting, digging, building, with a variety of incomprehensible machines — was in charge of robots. All the horizon that might be familiar to Naku, the green slopes of the valley and the forest above and beyond; was shut away by the high red ramparts.

Naku's captor carried him straight to the space ship, and in. At once Naku felt a strange lightness, as though he could float. The gravity screen of the vessel was set to the pull of Mars. Inside a cubical compartment, the robot thrust him into a chair, strapped his wrists to the arms arid his ankles to the forelegs. Then it stumped out. The Martian who smiled seated himself opposite Naku, before a flat-topped piece of furniture studded with push-buttons, levers and gauges.

THE Martian pressed a lever. Another of those strange light-rays, with which the invaders seemed to do so much of their working and fighting, gushed out — a soft cloud of orange radiance. It smote Naku full in the face, but did not blind or irk him. He felt all fuzzy inside his skull for an instant, then more awake than ever before. The Martian's smile grew broader, more understanding. For the first time, his lips moved and he spoke.

And Naku could understand him.

"Do not be afraid," he was saying, "and do not be mistrustful. This ray frequency makes our thoughts communicable one to the other. My name is Vwil, and I come from another world, another star."

"Then go back to that other star," said Naku at once. "We do not want you here." A rueful smile from Vwil, as though he would like Lone Hunt to be friendly.

"Our world is poor, starving," Vwil argued. "We have flown here in hopes of finding a place that will support life for ourselves, our comrades, and our children to come. Your world is larger than ours. It is rich, with much vegetation and water and air. There is room here for both your people and mine."

"I cannot live as a neighbor of the Thunderer," snapped Naku. "I have killed some of your people — two of the thin, red-faced ones like you, and one of the big shiny ones with a round light for a face."

He stared at Vwil, and his young eyes were as hard and sharp as war-axes.

"If I was free this moment, I would kill you."

"It is you who want to fight, not I," Vwil replied with a sigh. "What is your name?" Naku told him, and Vwil continued: "You started the fight, Naku. Yet, I think we can be friends. This ray of light makes it possible for us to talk. Can we not touch hands and be helpful to each other?"

Naku wagged his head in fierce negation. "I used to know this valley," he said. "It was peaceful, silent, green. Deer ate grass, and birds flew over it. Now you have built this fort and killed the grass. You swallow the very ground. Only the Thunderer spreads its wings — and the Thunderer is not alive, but a tool, a flying house," he added, remembering what the girl Arla had told him. "You have fought my people once, and beaten them. But there are others, Vwil the Invader. Many others, more than you can count — tribes and nations of fighting warriors!"

His chest swelled, as for the first time in his life he considered all mankind as a single battling unit.

You may beat others, but those who live will learn your secrets to use against you. Even I, a young man and a prisoner, have learned much in a little time. And in the end —"

"Wait!" came a new, cold voice.

Vwil rose from where he sat, and his attitude was respectful. A second Martian came and took the seat Vwil had quitted. His face was hard and full of ruthless wisdom.

"I have heard your soft words, Vwil," said the newcomer. "I disapprove. As commander, I will finish this interview. You may go."

VWIL departed from the chamber, but once he looked back. His brilliant eyes caught Naku's, who saw that they were full of pleading. Then the Martian commander addressed the captive:

"Let me tell you the truth of your situation and that of your people. You have boasted to that weakling, Vwil, of your triumph — two of us, and one of our robots have fallen before you. Let me bolster your conceit further, and inform you that these are all our losses — inflicted by your hand alone. The rest of your race has not done us one bit of harm. And you, being a prisoner here —"

I will escape," Naku promised him.

The commander smiled, not like Vwil, but as fiercely as a hungry wolf. His skull-face was a mass of crinkles, as hard and set as dried leather.

"I think not. Our first specimen of your race, the fat one with red hair on his chin, disappointed my experiments. He could neither be made to understand our speech, nor to receive the impulses of my will. You, under this ray, are more receptive."

So they had tried their tricks on Ipsar, and without success! Naku wondered about it. Was he not stronger of will, quicker of mind, than the pudgy priest? What shield, then, had Ipsar against the science of these invaders? If he, Naku, could get such a shield—

"Naku," the Martian chief was saying, his eyes fixing the young man's, "do you hear my words?"

"Of course I hear them," replied Naku.

"Do you obey me?"

"Obey you?" repeated Naku wrathfully, and met the blazing eyes opposite. He was ready to fight against his bonds, to burst them and leap at the contemptuous thing who presumed to set himself up as master .... but a new thought came. He was a captive. These were wiser, stronger beings. They must know best. Naku felt no surprise that his attitude changed so suddenly, under the green gaze of the spider-man with the lean red face.

"I obey you," said Naku humbly.

"You know," continued the inexorable voice, "that we, being desperate for life, are justified in coming from our poor world to your rich one — that it is our place to rule and yours to serve."

Of course that was the truth, Naku realized. Just as man could conquer and exploit the animals, so could these Thunder Folk, being wiser and stronger, conquer and exploit man. It was a law of nature, said Naku to himself — he should be grateful that he was allowed to live. So completely had Naku's attitude changed under the suggestive power of the Martian.

"It is your place to rule," Naku repeated, "and mine to serve."

"Good." The commander rose, came to him, and unfastened his bonds with a deft flip of the buckles. Naku rose respectfully.

"I have hopes of your kind," announced the commander. "Be good servants, recognize your subordinate position, and you shall live — prosper, even — under our rule. Now, return to your cage."

Submissively, Naku did so.

"AND so," the Martian commander finished his report to Vwil, "I succeeded. The exertion of my will-power, while the ray was turned on, conquered the creature's primitive individuality on the instant. Henceforth he will understand and obey us. When one of us meets his eye and speaks his will, the creature will carry out the order. These natives who call themselves 'men' are slaves ready to our hand — physically strong and adroit, cheaper than robots, intelligent enough to receive thought-impulses and obey, but not to overthrow."

"That is interesting," said Vwil. "I am sorry that I cannot report so encouragingly on my own labor."

"Your own labor?" repeated his chief. "What have you been doing?"

Vwil held out a chart, on which he had noted various chemical figures.

"It is the question of fuel. We have not enough to return to Mars."

"We can manufacture more when the time is ripe," snapped the commander. He was irritated once more with Vwil. This enigmatically gentle scientist, so brilliant and yet so weak from the Martian standpoint, was always a challenge. Just now the commander had recited his triumph over Lone Hunt, not as a leader informing a subordinate, but as a subordinate seeking the commendation of a leader. And Vwil, unimpressed, had only admitted his own failure in another field.

"This planet, however rich, lacks certain necessary elements," Vwil was saying. "Also, the explosive power of metals seems subdued. I fear that we cannot manufacture proper fuel — we are stranded."

"Let it be so," growled the commander. Suddenly he felt more ruthless and determined than ever. "We shall make ourselves lords of this world. The men whom we capture shall serve us in a closer capacity than as slaves or robots." His eyes glittered a brighter green. "Listen, Vwil, to what I plan."


"Our brains are great, but our bodies weak. These natives, less developed of mind than we, have yet strong bodies, well adapted to the particular life-struggle here. The inference is obvious."

"Perhaps," said Vwil. "Yet I do not approve —"

"Once more, I remind you that I command. We shall transplant our brains to their bodies. We will become immortal, even — as a body grows old, we can shift the Martian brain in it to a new, young body. Always we shall take the finest physiques for ourselves, and the rest of the human race shall serve as slaves. When more of our people come —"

"Will more come?"

"We cannot return, as you have shown," said the commander. "Unless we do return, reporting this planet as unfit for habitation, others will follow to see what has become of us. We, the pioneers, will be also the chiefs and heroes of the new colony of Mars."

His voice rose exultantly, his lean face was suffused with a darker red. It was as though he saw the enslavement and exploitation of all humanity achieved, the complete control of Mother Earth in the bony hands of his own invading race.

"Let the flying detail go and seek for more good specimens," he rasped. "Let them bring only the finest, killing all others. Meanwhile, we must experiment. Who is our dullest brain, the one with whom we can experiment most cheaply? Bring him to the surgery, also that fat fool among the prisoners, and make ready for an operation."



The Shell Cap

A DAY and a night had passed since Naku had been returned to the cage from his interview with Vwil and the Martian leader. Away from the influence of the Martian, he could once again think for himself. With the dawn, the flying machine — Naku no longer thought of it as the living Thunderer, but as what Arla had pronounced it, a complicated tool — came winging back from another expedition. it had swooped at night upon a camped hunting party, killed two men and captured a third. As robots led this hunter to the prison, Arla sprang up from where she lay asleep on soft sand.

"Lumbo!" she cried, in a voice that betrayed both happy surprise and concerned question. The young man in the grip of the robots was a blond-haired, blue-eyed specimen like herself, and his face — it was as handsome as her own, but with masculine strength of contour — lighted up in recognition. He was thrust in, and Arla seized him in welcoming embrace.

"They have not hurt you?" she demanded in tender concern.

Naku watched, with feelings he did not bother to diagnose, since they were strangely glum. He had known Arla only a few hours, and up to now had not had the time to consider whether she was desirable or not, until this stranger suddenly claimed her affectionate attention. He must be her husband or lover — and Naku suddenly disliked the idea.

He turned over in his mind thought of a sudden plan to provoke a quarrel with the blond youth. It would lead to a fight, with Arla as prize of victory. Naku gauged the other's volume of muscle, his quickness of reaction. Probably here was a good fighter and ready, but Naku felt himself to be both stronger and fiercer ....

The robots who had brought the man called Lumbo had also roused fat Ipsar from slumber and dragged him out. Ipsar struggled and protested, and the seashell cap fell from his tossing head and lay just inside the barred door as it slammed behind him. Arla turned toward Naku, her blue eyes filled with flecks of golden joy-light.

"Naku," she said, "this is my brother, Lumbo — the son of my father and mother. He was surprised and captured by these Thunder Folk, but now he is here, with you and me. The three of us are wise and strong. We will find a way to escape."

Her brother! Naku's dark, square-jawed face glowed with a joy to match Arla's own. His welcoming hand caught Lumbo's and squeezed it until the other winced.

"I am glad to see you," said Naku honestly. "Glad that you are Arla's brother." Arla bowed her head shyly — she, at least, understood the inference. Lumbo rejoined courteously, and added: "Arla is right. We three should win out of this trap, Tell me what you know of our captors."

The trio of young people sat on the sand, Lumbo in the center. Arla and Naku alternated in setting forth both observation and theory. At the end, Lumbo summed up:

"We are unarmed, and caught like fish in a net. But," he added weightily, "from what I have seen and from what you tell me, I have it in mind that we are also like netted fish in that those who caught us must work clumsily with us, like fishermen wading and swimming in water. I mean that these stranger people, whom Naku calls the Thunder Folk, do not feel natural upon our world. Light weights are heavy to them, and the air is thick to their breathing. We, who are used to these things, have the advantage by at least that much:'

HE PAUSED to let the idea sink in, and picked up the shell cap that Ipsar had dropped.

"What is this thing?" he asked. "Does it belong to the Thunder Folk?"

"It was the cap worn by Ipsar," Naku replied. "He wore it to show that he was a priest." Taking it from Lumbo's hands, Naku set it upon his own shaggy black hair to demonstrate. The thing fitted snugly, and weighed little. The three prisoners continued their talk, and Naku forgot that he wore the shell.

Meal time came, and it was Vwil who brought food in his own spidery hands — metal bowls, in which were contained sliced roast meats and several kinds of fruit. He spoke in friendly fashion to Naku, but his purring words were unintelligible. Naku shook his shell-capped head, and both he and Vwil stared uncomprehendingly. They had understood each other well the day before, in the space-ship. What was wrong now?

Naku, perplexed, lifted a hand to rumple his hair. That hand twitched back the shell cap, and at once he knew what Vwil was saying in the language of the Martians,

"Answer me, Naku. I am still ready to be your friend, to help you if I can. Do not pretend to be deaf."

"I am not deaf," grumbled Naku, and Vwil also understood. "It seems that —" He was about to say that the knowledge of Vwil's language had seemed to escape him for a moment, but on impulse he broke off. Dropping his hand from his head, he let the shell settle back into place. At once he was unable to comprehend Vwil's words, but the Martian's manner suggested a friendly farewell. Left alone, the three began to eat, and Naku and something amazing to relate.

"I could understand him, and he could understand me, only when I pushed back this shell cap," Naku informed the others. "When I have it on my head, he speaks strange words."

"We did not understand him at any time," contributed the girl Arla, sinking her white teeth into a big yellow plum.

That was an additional item to consider, pondered Naku. He remembered the orange ray, and how Vwil apparently used it to establish communication with him. Arla and Lumbo, who had never felt that ray, could not understand. The consideration extended itself; they would never understand the Martians until the ray was played upon them.

Naku remembered something else. The Martian commander had spoken of Ipsar, had said: "He could neither be made to understand our speech, nor to receive the impulses of our will." Naku took the shell from his head and gazed at it. Yes, Ipsar had worn that shell until his recent struggle with the robots. Naku, wearing it, had shut away the understanding of Vwil's words, as a wall might shut away light — even the light of the orange ray. What did it portend?

FORGETTING to eat, Naku groped for a decision Again he studied the shell. It was of unthinkable age, enameled with the stony lime of petrification, and it hid his thoughts from the Martians. Naku, like all his people, believed that the heart, not the brain, was the seat of the reason and the emotions, and so the idea of an insulated brain-case was not easy to grasp. But the facts were before him, and he decided to accept them.

He considered, too, that the ray-induced ability to understand the Martians also bent one's will to those strange and forbidding creatures. The commander had said so, and had demonstrated it. But he, Naku, had the shell-cap. Without it, he could understand the Martians, benefit by what they said. Wearing it, he could withstand their wills. Naku began to think that here was a chance for escape — even victory.

Lumbo was haranguing his sisters on that very subject.

"Without beating these Thunder Folk, destroying them, it makes no difference how far we run from them. What they say and do shows that they intend to rule the world, and us. We must fight — win."

So they all talked. Naku kept the shell cap on his head lest a Martian, passing, overhear and understand him and report that the captives plotted. He also stared through the bars at the garrison, their buildings and equipment, and at the walls that seemed ever to grow and embrace more territory. Soon these walls would enclose the whole valley, encroach on the forest. Would the fortress eventually overflow all the world?

In he midst of this, figures approached. All three looked up. Two robots came, and the Martian commander, and Ipsar the priest.

But Ipsar no longer went in a prisoning grip — he walked beside the commander, who leaned for support on the fat shoulder. Ipsar's cranium was swathed in white bandages, and seemed to have swelled beneath them. He spoke, and the voice was Ipsar's, but the words — they were in the language of the Martians!

Wondering, only half guessing, Naku whipped off the insulating cap. At once he made out the words, and they were addressed to himself:

"You with the black hair, prepare to go with this party." With his own plump hand, Ipsar unfastened the barred doorway. "Come forward, I tell you."

"Come out," seconded the commander, catching Naku's eyes, and Naku obediently emerged. "What do you hold in your hand, that stony thing like a bowl?"

Ipsar closed the gates upon the staring Arla and Lumbo, and came close to Naku. "Yes," he said curiously, "what is that?"

His query saved Naku, saved mankind, saved the world. For the young man held by the will of the commander, would have replied truthfully and fully concerning the cap's power to shut off thought-impulses. But Ipsar's evident ignorance of the object he had worn so long and constantly made Naku turn toward him.

"Do you know what it is? You, as priest, had it always on your head."

"Did I?" And Ipsar took the cap, lifting it to his bandaged pate. But the swathings and the enlargement made it impossible to fit the shell in place.

"I will wear it no more," he announced. "Here, prisoner, it is yours." Contemptuously he slapped it upon Naku's head, and at once the next speech of the commander slid into unintelligible purrings and snortings. Naku could not understand them — and could not feel the impulse to obey in his heart.

When he did not act upon whatever order was given him, the commander fiercely repeated it, and pointed toward the center of the fortress, where the space-ship still lodged. Ipsar, on the other side of Naku, was also speaking in the Martian tongue, but, like the commander, was only astonished and not suspicious at all at the captive's lagging. Sure of their psychic control over Naku, neither appealed to the robots.

NAKU made up his mind at once. He took a step toward the ship, and the robots also turned away, leading the party toward it. At once Naku went into action. A backhanded flip of his big left fist sent the commander spinning head over heels like a straw figure. Whirling without an instant's pause, Naku struck with both hands at Ipsar. His left sank into the priest's flabby belly and, as Ipsar doubled over, Naku's right landed flush on his bearded mouth.

Down went Ipsar, and from behind the bars of the cage both Arla and Lumbo cheered loudly. Naku did not wait to acknowledge the applause. Already the robots turned toward him. One held a ray-throwing rod.

Springing across the floundering form of Ipsar, Naku fled for his life in among the buildings of the Martian settlement.



In the Mammoth Pen

TWO buildings, square storehouses, were set so closely together that Naku had to squeeze between them. But he hesitated only a moment to do it, not caring that bits of skin were scraped from the points of his broad shoulder. Behind the houses was an alley, and into this the two robots were already dashing from either end. Because Naku seemed trapped between them, and also to avoid injuring its companion, the robot with the ray-device did not use it.

But Naku saw a wall or paling, of the red tile-like substance that the controlled atomic machines made out of plain earth. He charged at it and dived over, head first, though it was as tall as he. Landing on hands and knees beyond, he waited a breathless moment. The robots could not follow him, and he heard them clanking away to cut him off beyond. Like a fox he doubled, hurling himself back across the wall and into the alley. Up this he tore, just behind the robot with the ray-rod.

There was an open street at the end of the alley, and across this he made a dash. Shouts greeted his appearance — full half a dozen armed Martians had gathered at the call of their leader, and moved to bring him to bay against a wall. But Naku was an outdoor man, thrice as strong and active as the most vigorous Martian, and the wall had inequalities enough to give him hand and foot holds. He swarmed up like a monkey. A flame-ray struck just where he had been as he mounted, turning the red of the wall to cindery black. Then he was over the coping. He had hoped to land in open country, but this part of the wall, once the outer rampart, had been passed by the encroaching works of the Martians. Beyond it was a higher wall, and the space between was full of sheds, shelters, and stacks of metal and other materials. It contained, too, a great pen or cage of metal bars with a flat earthen slab for roof — a structure similar to that in which he had been held, but larger and more coarsely made. He could thrust himself between those bars; and, with the noise of pursuit greatening behind him, that is what he did.

He raced to the cage, squeezed in, without more than glancing at the great brown-black lumps that seemed to pulsate inside. Anything, he told himself, was less terrible and more practicable to deal with than Martians or their robot-slaves — and, even when he saw that the tenants of this enclosure were mammoths, he did not emerge again. For the Martians, four of them, accompanied by armed robots, were coming into view; through ports in the wall. Naku flung himself at full length into a heap of grassy forage which the Martians had sagely given to the captive beasts.

Here he lay still.

There were three mammoths, male, female and calf — great shaggy mountains of flesh more than twice a tall man's height at the blocky shoulders. Their woolly skulls were high-domed, the index of cunning brains that were mirrored in their tiny, questing eyes. Their legs were like living tree-trunks, covered with hair like thick, coarse moss. And their trunks, as pliable as anacondas and clever as hands, now began to swing and writhe. They squealed and muttered, to each other. The sudden appearance of their chief enemy, man, alarmed and infuriated them.

THEY moved, all three as one, toward the heap of grass into which Naku was burrowing. He felt, rather than saw, their great hillocky bodies above him. He heard the rumbling intake of their breath, the rustle of the trunks that began to squirm about him. The Martians, toward which he dared not lift his face, were patrolling near the cage, shouting to each other and to the robots. A mammoth's trunk groped along the calf of Naku's leg, paused on his bare back, and tweaked his flesh painfully. Naku stoically refused to twitch or gasp. The largest mammoth, changing position, set a massive foot within arm's length of Naku's head, and also explored with its trunk. The top of the member found the shell that covered Naku's cranium, prodded it tentatively, and dislodged it.

At once Naku could comprehend the speech of the Martians. Even in the midst of peril from the mammoths, he listened carefully. The commander was doing all of the talking:

"We may have underestimated these beings that call themselves human. At first the black-haired specimen seemed completely under control, but in some way it wore off. Well, he must have gone over our wall. Go, two of you, on a flying detail. If you catch him, bomb or ray him. He knows too much to be allowed life."

Naku exulted in his hiding. The wise, harsh chief of the enemy was mistaken about him — and afraid of him, eager for his death: Naku swore that in this last case he would disappoint the commander; and then he felt the trunk-tip of the largest mammoth combing his hair. The big beast was snarling to itself, shifting ponderously on its feet, trying to guess what lay so still among the heaped grass, smelling of man but not moving. And the Martians heard.

"Those animals we captured are nervous," one of them said to the commander. "Let us see what they do."

The commander approved, and the party came near. The big mammoth, seeing his captors approach, moved grumpily forward to the bars. A foot swept across Naku's prostrate back, barely a palm's breadth above it, then another. The fugitive, daring to glance up, saw that he now lay under the hair-thicketed belly.

Sensible of his mortal peril, yet he knew that he was for the moment hidden as under a shadowy roof. The Martians were conversing just outside the bars.

"Fix the thing's eyes with yours," the commander was telling one. "See if you can read its mind — impossible, you think? There is something wrong here, but the animal's brain is too primitive to communicate its impressions to ours."

"That is true," agreed the Martian addressed. "Probably these beasts saw the escaped human run near their cage, and climb over the outer wall."

"Probably," said the commander. "If I could but fix that black-haired one's eyes with mine again, I might subdue his will. But time is too short for experimenting. I am weary of walking on this thrice-gravitied planet. Let them bring that other male, the one with the yellow hair, to the operating room."

They moved away. Naku slipped stealthily from under the mammoth's belly, around its massive hindquarters and into the back of the cage. The big beasts stood together, watching the departure of the Martians. Naku found a space between the rear-hindmost bars and the adjacent partition, a place where he could lie and be safe both from the blundering ill-will of the mammoths and the discovery of the Martians.

HE RECKONED up the evidence in what he had just heard. The commander of the enemy had said something about wishing to look him in the eye. In such a gaze, then, must lie the power to enslave one's will. Naku decided never to look another Martian in the eye, especially when he did not wear the shell cap. Then he looked for the shell cap — it still lay among the cut grass at the front of the mammoth's cage. And, hearing the ill-tempered squeals and snorts from the three giants, Naku dared not go back just now for it.

He continued his diagnosis of the Martians' conversation. Lacking Naku, the commander ordered that "the other male, the one with yellow hair" be brought out. That would be Lumbo. What was to happen to Naku's new friend?

His meditations were interrupted by a low menacing growl, at his very ear. He whirled over in terror. Nothing was there but the wall. From behind it came another growl. Naku guessed at once that a cave-lion, perhaps several, were penned up next to the mammoths, and that they smelled him where he lay.

"Lions and mammoths," he thought. "These Thunder Folk hold them safe in traps now, and have nothing to fear. But suppose that they, and whatever other animals are captured, should be let loose?" He smiled tightly, and his eyes shone at the thought.

But he remained where he was, perforce, while the sun passed zenith and slid down, down, to the horizon and beneath it. He heard bustlings in the open and, once the takeoff of the flying machine. The enemy sought him afar — not here.

When dark came, he slipped from his hiding.

The Martian camp was lighted here and there by flares of a dozen colors and intensities — the gleam of rays that delved, built or modified things according to the will of their operators. But there were plenty of shadows, and Naku, subtle hunter and woodsman that he was, knew how to take advantage of them, hide in their hearts, pick his course from one to another. Even in the face of passing Martians and robots — there seemed to be more of these latter than before, as though the invaders built new ones of materials prepared in the camp — Naku retraced his steps across the inner wall, up the alley and between the storage sheds until he was again in sight of the cage where he had been held prisoner.

He gazed long and critically through the gloom, and saw only one figure inside — a slender, dejected figure, that of the girl Arla. He approached cautiously and lay in a blot of darkness.

"Arla!" he called softly. "It is Naku, escaped from the Thunder Folk. I am hungry and thirsty. Is there anything left from your evening meal?"

She turned toward him, made a sign with her hand to show that she understood, and came close to where he had crept up against the bars. First she handed out a bowl of water, which he drained gratefully; then a platter of meat and cooked herbs. Naku began to eat ravenously, but he saw that she trembled and heard her sob to herself.

"You are crying," he said. "Why? They have taken away your brother Lumbo, is that it?"

"Yes," she replied brokenly. "He fought, but the shiny things that look like men but are only walking, wrestling tools — two of them dragged him away. Naku," she addressed him earnestly, "you must leave here, or awful things will happen to you, too."

NAKU emphatically shook his head. "No, Arla. Up until now, I have outfought and outwitted these powerful Thunder Folk. I shall do so still. I shall not leave here until you are free also."

"But they will catch you and do terrible things. I am afraid that my poor brother —"

"Did they take him to that great round shiny house in the middle?" Naku meant the space-ship. "Listen, Arla. I will go and spy on them. I will save your brother." He said it as if he already saw a way to succeed, and his confident words put an end to her sobs. She put out a hand between the bars. It was a slim hand but strong, and it clutched Naku's own broad one and seemed to draw strength from him. Naku squeezed her fingers encouragingly.

"Be brave, Arla," he begged. "I will not desert you. I am Naku — wiser and stronger and braver than the Thunder Folk — and I like you." Again she seemed to believe, to win hope from his own confidence. As for Naku, he warmed to her still more.

"Arla," he said, "you are from a stranger people, whose customs I do not know. Do you know what a kiss is?"

"A kiss?" she repeated. "Oh, you mean — like this?"

Their heads carne close together, and their mouths touched through the bars. "You must go now," she whispered.

"I will go, but to find and save Lumbo," he replied, and crept away.

Still taking advantage of sheltering patches of shadow, he approached the space-ship. Its ports were mostly open, and one of them gave off light. Naku came to it, and found it above his head. But nearby was a great block of wood, from which the Martians had cut lumps for their building. Naku dragged it close, stood upon it, and peeped into a chamber of the craft — the chamber which the Martians used as a surgical operating room.



Naku Finds Allies

NAKU could see plainly all that happened in that room.

Upon two raised metal slabs lay prone figures. The nearest of these was Lumbo, the brother of Arla, fastened down by bands at wrist and ankle, around the middle and the neck. He lay still and pale, but not dead — even though his blond head was cleft apart and a Martian fumbled inside his skull with twiglike fingers. Upon him played a green light one of those myriad rays with which the Martians accomplished their wonders.

On the other slab sprawled a Martian, the commander himself. But it could not be, Naku mused wonderingly — for near him stood two of his subordinates, and they were plainly doing him harm! One, plying a gleaming instrument like a knife, but with a tip that whirred like a dragon-fly's wing, was making a hole in his brow. The other held the top of his chief's huge cranium and, as the one with the knife cut it away, lifted loose the skull-cap like a bowl.

"Hurry," said the one who stood by the unconscious Lumbo. "We are at the moment for which we have labored these many hours. Spray the brain with the life-ray."

A companion did so, using a nozzle that gushed green light.

"Now, then, into this other cranium." From the cut-away skull of the Martian commander deft hands drew a crinkled gray lump, like a huge nutmeat. Naku saw it for a brief instant as it was carefully slid into the cleft in Lumbo's head. The operators exclaimed in triumph, and turned on the green light more strongly. It seemed to heal, to some degree, Lumbo's wound, though his brow bulged with the extra volume of brain it now contained. After a moment he stirred, stretched and spoke:

"Unfasten these shackles, someone."

As Naku stared and wondered, the operators hurriedly did so. Lumbo, so lately their prisoner, sat up on the edge of his slab and pointed to the silent form of their commander.

"Throw that carrion away," he directed, and a robot lugged it out through a panelway.

"I feel splendid," went on Lumbo, stretching luxuriously. "I can understand how the primitive natives of this planet can set so much store by physical health. And my intellect, I am sure, is not impaired by so much as an atom's force."

The Martians agreed sycophantically, and one began to bandage the half-healed cranium. Naku was torn between utter amazement and utter delight. In some way his friend Lumbo had established command over these enemies. Perhaps it was because he had not died of that fearful wound in the head — they might think he was a mighty magician. But then, they had seemed to work hard to cure him. Naku scowled. His own head ached with the labor of trying to understand.

ANOTHER figure entered. It was Ipsar. Lurnbo, as the bandage was swaddled around his brow, addressed the priest: "The operation was a success. It will follow with others, as swiftly as I obtain prime specimens of the human race to replace our own bodies. But I have orders for you."

"Yes," nodded Ipsar respectfully.

"It is possible — probable, even — that we can pass on our mental powers and other characteristics to human progeny; the children, that is, of these new bodies of ours and females of the human race."

"Yes," repeated Ipsar.

"We have one female prisoner. I give her to you for a mate. And now leave me — I have had little enough rest since I arrived."

He stretched out on the slab, and closed his eyes. A robot moved forward, as if on guard. The others departed.

To Naku there were many mysteries. The fact that Lumbo's body was now governed by the Martian chief's brain he could not grasp. The things spoken by that brain through Lumbo's mouth registered only vaguely, smacking to Naku of some strange occult viewpoint. But one thing was certain — Lumbo had told Ipsar that he might have the captive Arla for a mate.

Naku stepped down from his block of wood. He could understand that thing least of all. Did Lumbo think to bribe Ipsar into an alliance? Was he not powerful enough already, in whatever strange way he had taken to seize control of the Martian party? Or was it that he valued his sister lightly, and cared little whom she might marry? Brothers were sometimes like that — but Naku was no brother of Arla. He had other hopes about her.

He saw fat Ipsar, tramping across to the cage, and followed quickly and silently, keeping yet again to the shadows. The priest deftly unfastened the gate and entered. After a moment Naku heard Arla cry out in fear:

"No! Let go of me!"

"Little fool," Ipsar was replying angrily, "you will be far better off than most females — they will become like a race of robots. You, as my mate, will have the advantage of —"

"I cannot understand your talk," Arla gasped. "Let go!''

Naku charged the door, sprang into the cage. Ipsar held Arla by her wrists, but with a single clutch and heave Naku tore the two apart from each other. Then he smote Ipsar in the center of the face that sent him staggering back into a corner.

"Arla is mine," Naku growled at him. "Do not move toward her, or I will kill you." Ipsar did not move toward Arla. He was tugging something from a loop in his girdle — something that gleamed, even in the dimness of the cage. Naku had seen too many ray-rods in the past day or so to mistake this one. He made a quick, overwhelming lunge. Down went Ipsar again, giving one hoarse howl for assistance. Then Naku's right hand clamped over his mouth, and Naku's left hand imprisoned his weapon arm.

"Run!" Naku bade Arla. "The door is open — run and hide!"

SHE needed no second bidding — she was gone. Naku wrung Ipsar's fat wrist until the ray-rod fell from his hand, then switched his left grip to the throat.

"Traitor!" he growled at the priest. "You turn against your own people to help these devils from another star," and his fingers, digging through the frill of red beard, sank into Ipsar's windpipe. Naku rose to his feet, dragging Ipsar with him. He bent the pudgy form across his knee, bent it back, back — he heard the snap of the spine. Ipsar went limp.

Dropping the body, Naku turned to follow Arla into the open, but there was a sudden malevolent clanking, and a robot towered in the doorway. Its face-lamp glowed as it peered in. Its claws held a ray-rod.

In desperation, Naku snatched up a ray-rod of his own — the fallen weapon of Ipsar. He pointed the lens-end toward the figure of metal. His hand found a yielding stud upon the rod's smooth surface, and he pressed it as he had seen the Martians and robots do.

Out gushed a finger-narrow streak of flame, straight at the center of the robot's torso. There was a sudden clangor, a red-hot glow of the creature's metal, and then it fell noisily. Naku, releasing the switch, saw his weapon's ray subside. He ran, jumped across the prostrate robot, and was free.

Arla was nowhere in sight. Like himself, she would know how to take advantage of the shadows. But there was a commotion all through the fortress. Robots were moving hither and thither, singly and in little groups, with Martians stumping around in command.

"I have made too much noise," Naku told himself savagely.

Once again he fled for the only quarter of the camp he knew anything about — between the storehouses, up the alley and to the old rampart wall that was now an inner fence. Up this he swarmed, and a searching Martian saw his silhouette against the night sky, yelled and pointed. There was a rush of feet, both metal and living, as robots and their masters converged in pursuit.

Naku slid down on the other side of the wall, glaring wildly to left and right. He saw once more the pen where the mammoths were confined, the same that had given him such precarious asylum earlier in the day. Again he was inspired.

"Hai, mammoths!" he shouted, rushing up. "Great hairy ones, mountains of meat — prepare to come out and fight for your lives!"

The three mighty things cocked their great fanlike ears, as though they understood. Naku came close and turned his ray-rod against the fastenings of the big barred door.

His pursuers were in sight now, and yelled to each other in triumph. But they did not ray him at once, for he stood among their shelters and possessions, and a flash of heat might destroy other things beside this troublesome human savage. Meanwhile Naku had destroyed the big locked catch, and with all his strength dragged the door back on its hinges.

The largest mammoth, disgruntled at the commotion in front of him, rolled out immediately. The Martians saw that he was free, cried out in alarm, and drew back together in a little group. The mammoth hoisted its trunk, trumpeted, and hurled its great bulk forward.

The other two scrambled heavily to follow their leader.

Naku, crouching low to let the rush go by, sped on to the next cage.

"Ho, you lions in there!" he cried, in fierce gaiety. "You, too, shall be let out to battle!"

The big cats hissed at his shouts, which they could not understand. But when he rayed the lock from their door and dragged it open, they understood that. Out they came, in a tawny torrent, and dashed in sudden rage for the place of greatest noise and commotion.

VWIL, roused from his laboratory work in a shed near the space ship, ran out into the night to investigate the growing commotion. His meager muscles made it a slow journey to the quarter where the captured animals were kept, and already the mammoths were out and had rushed the party that searched for Naku.

Two Martians and six robots made up that party. Though they had ray-rods, they forebore to use them for a moment, fearing to injure valuable property. After that, it was too late. The biggest beast trod on a robot as on a beetle, smashing it into a welter of case-fragments and wheels and wires, then caught another in his trunk and hurled it far over a shed.

The other robots stood their ground, threatening with their weapons. But the two Martians, able to know fear and caution, retreated into a squat building that housed a half-assembled atomic motor. The two smaller mammoths began systematically to tear it to pieces with their trunks.

"Get into the open!" Vwil yelled to his companions. "Use your rays!" Suiting action to word, he turned his own ray-rod on the biggest mammoth, the full force of the leaping heat-flash striking it broadside in the region of the heart. The monster screamed once, then fell abruptly silent. The flame had torn clear through its huge bulk, killing it instantly. It collapsed, gushing smoke that gave off a disgusting burnt odor, almost overwhelming the robots.

Heartened, the cowering pair in the motor-shed peeped out and leveled their rays. The smallest mammoth, less angry and perhaps more intelligent than his fellows, backed up as by instinct of danger, but the other took the full impact of both discharges in the head, and keeled over heavily upon the hardened pavement. At that moment the fight seemed won.

But other forms were maneuvering in the open space, lithe and menacing forms. The lions were loose. Somewhere farther along sounded the truculent bellow of a wakened bison.



The Battle of the Beasts

NAKU, hurrying down the row of cages, rayed open door after door. All the brute inmates thankfully emerged — the mammoths and lions were quickly joined in freedom by a bull bison, half a dozen frantic deer, three great apes of a species that ordinarily Naku would avoid, and a vast and grumpy cave-bear. As he freed each, Naku ducked around the corner of the pen, and the beasts gravitated toward the commotion in the center of the open.

Turning from the bear's prison, last of the cages, Naku came face to face with a robot. He lifted the ray-rod, which he regarded by now as a familiar weapon, and pressed the switch; but it gave forth no flame. Its charge was exhausted. The robot took a clanking stride forward, its talons extended to seize Naku.

At that moment something rose behind it, even bulkier and more terrible than itself. The released cave-bear had come erect upon its rear legs, and was as much taller than the robot as the robot was taller than Naku. Two sturdy, shaggy forepaws extended and encircled the round metal torso.

Naku retreated, but over his shoulder he watched the struggle with fascination. The robot tried to jerk free, but the fleshy arms of the bear were too strong for its mechanical lurchings. It reached back a claw, clutched and tweaked a furry shoulder. The bear roared, swung a paw, as a man strikes a fly with a flat palm. The metal skull of the robot, which could turn the most desperate blow of a war-axe, collapsed under the weight of that buffet. The bear shoved the tottering hulk aside and moved toward the thick of the fight.

Naku gained the inner wall and mounted it. Once again he looked back — the animals were being destroyed by freely-used rays, but these same rays had set a dozen fires among inflammable dumps and stores. Even the hardened earth seemed to collapse and reek before the glowing spears of pure heat.

"This place may burn to nothing," Naku told himself. "I must find Arla — yes, and Lumbo. I promised to rescue Lumbo."

He ran back toward the space-ship, not taking so much trouble to stay in the shadows, for he saw neither Martians nor robots. They must have gathered to deal with the loosed animals in the cage-quarter. Once he dared call out for Arla, but there was no response. Perhaps, he considered, she might have won clear from the fortress, would be waiting outside. After he had found Lumbo and helped him to safety, Naku would look for her, find her. That would be pleasant.

He came to the great round hull of the ship, moved cautiously along its side, and located a door. It was shut, but not locked. After a moment he solved the trick of its fastening, pushed it back and entered. Inside, he found himself once more light and springy, as though two-thirds of his weight had been taken away. He was able to move silently down a metal-faced corridor. A table stood against one bulkhead, with a ray-rod upon it. He picked up the weapon, and advanced more confidently.

COMING to the entrance of a compartment, he saw a Martian inside, seated before a complicated mass of machinery-wheels, bobbing levers, electrodes that gave off rhythmic bands of sparks. From the various terminals rose pulsating rays in all colors of the rainbow. The Martian kept it in operation by constant pressing and shifting of an intricate system of keys, buttons and switches.

"Thunder Creature," Naku addressed the operator, "stop that work."

The Martian turned upon his seat. He looked at the leveled ray-rod, and was afraid.

"You are the human prisoner who escaped," he said shakily to Naku. "Be careful of that thing you hold. It might cause damage — you do not know its power —"

"But I do know its power," Naku assured him. "With another thing like it I have killed some of your brothers, and have burned open the doors of all the prisons in which you held beasts. What is that tangle of stuff you work with, making to move and light up? It is a tool, I think, like the flying house and the man-shapes with lamps in their heads."

The Martian, helpless but plucky, was silent.

"Tell me, or I will burn it with this weapon," Naku insisted. "No, do not stop to make a lie in your heart. And do not try to catch my eyes, I will not look at them." The ray-rod in his hands threatened the machinery.

"Do not destroy it," begged the Martian. "This is the basic-power machine — the broadcaster of energy to all our affairs. If it were damaged, the flying machine could not lift from the ground, the robots could not move, the very ray-rods could not be charged when exhausted —"

"It seems," broke in Naku, "that without this thing running and dancing and shining like that, you would be weak and easily conquered. Is that not so? Well, I shall wreck it."

He sent a gush of heat-ray into the heart of the mechanism. It grated, emitted a puff of oily vapor, and halted abruptly, its lights dimming.

The Martian gave a wail of dismay, and sprang wildly at him. Naku laughed fiercely, and swung the ray-rod like a club. His assailant went over like a reed in a hurricane, and lay still.

Abruptly, there rose new pandemonium outside, yells of mortal terror from Martian throats. Their lights had gone out, their machines had ceased running. Even their robot slaves, powered by the energy waves from the machine Naku had wrecked, were suddenly stilled. Only the ray-rods, each charged temporarily, remained potent against the heterogeneous swarm of brutes they fought. The Martians began to retreat toward their ship.

It was dark in there, too, but Naku was wise in night movements. He groped along the wall to another opening, from which came a gentle filtering of light. It was a chamber with an open port, and the flickering fires among the cages in the middle distance gave a little glow there — enough for Naku to see a stiff-frozen robot in a corner, a pair of slabs, a shelf of surgical instruments and other materials, and the outstretched form of Lumbo.

HE went to the side of Arla's brother and nudged him.

"Lumbo," he called softly. "It is I, Naku, come to save you. Wake up, Lumbo!" The blond youth stirred, sighed and awoke. Naku could not see his face in the dimness, but Lumbo evidently recognized him. A gusty snarl came from his mouth, and he sprang without warning upon Naku. A moment later the two were sprawling on the floor, Lumbo above, striking heavily at his would-be rescuer.

"I will kill you, black-hair," he panted between blows.

Naku blocked the worst of the punches with his crossed arms, then, recovering from his half-paralysis of surprise, shot his hands upward and pinned Lumbo's either biceps. With a sudden exertion of all his strength, he whirled the attacker sidewise and off of him. Rolling as he did so, he came up on top, pinning Lumbo against the cold metal floor.

"You are dreaming, Lumbo!" he cried. "I am no enemy, but Naku — we were captives together, and planned to escape and overthrow the Thunder Folk!" As Lumbo struggled, Naku tightened his grip. "Lie still," he warned. "I am stronger than you. If you force me to fight you —"

At those words, Lumbo relaxed.

"You are Naku," he said slowly, as though to inform himself. "Yes — yes, of course I remember. Let me up. We are friends, escaping together."

They rose and went out side by side, Lumbo's hand on Naku's shoulder. Naku decided that the other was still sick, perhaps a bit delirious. His head was heavily bandaged, and Naku remembered the strange behavior of Ipsar after such an experience. But there were other things to consider.

In the open, Naku displayed his ray-rod. "See," he addressed his friend. "This is a weapon of our enemies. It makes fire — so." And he spurted out flame, into the door of a shed. At once the place blazed up.

"You know how to operate it!" gasped Lumbo, and Naku did not take time to dream that Lumbo's surprise was other than that of joy. He was setting other fires.

"We will burn their whole camp," he announced. "Look, where the strongest fires are. I have let go the animals, and they fight the Thunder Folk."

"Then let us go that way," said Lurnbo at once, and started off swiftly, dragging Naku along.

Together they climbed the inner wall that Naku was getting to know well. Behind them the fires Naku had set were growing brighter. The battlefield they now saw was strewn with dead bodies — the beasts of Earth, the men of Mars, the fallen, empty robots — but no living thing stirred.

Lumbo bent over some of the corpses. "Most of my — most of the garrison must be dead," he pronounced. "The expedition is a failure."

"The animals are all slain, too," added Naku. He hurried to the pen where the mammoths had been kept. Its wooden joinings were afire, and the earthen roof flaking to bits. He could plainly see the interior.

With a cry of pleasure, he rushed in and snatched up something round and white, that had miraculously escaped the trampling feet of the mammoths. Then he hurried back to Lumbo.

"Look," he said. "This shell, that Ipsar wore, helped me to do what I have done. When I wore it, the language of the Thunder Folk was lost to me, and the will-power they exerted over me was brought to nothing.

"Is that true?" demanded Lumbo sharply. With a forefinger he tapped the shell experimentally. "Hmmrnm," he said as though to himself. "It is not impossible — no. Made by nature as an absolutely tight vessel, with no single orifice — then transmuted by ages into inert stone, of the finest insulating elements — it could prove practicable, though we never guessed it —"

NAKU did not know what the other was mumbling about.

"I wore it thus," went on Naku, and donned it.

Lurnbo was talking on — but in the purring language of the Martians.

Naku stared, felt a coldness oŁ fear about his heart, and lifted the thing from his head. Immediately he understood again.

"Do not put it on a second time," Lumbo commanded him earnestly, and fixed Naku's eyes with his. "Give it to me."

Submissively Naku handed the shell over, and Lumbo hurled it down. With a powerful kick he smashed it. His eyes held Naku's.

"You will obey me," he said.

"I will obey you," agreed Naku, "but what — what —"

"You cannot comprehend, of course. Let me say it simply. You call me by the name of your friend, Lumbo. This is his body — but the mind is that of another. Yes, the mind of the chief of your foeman. Without that petrified shell that deflected the will-impulses from your head, you can understand me. I hold you as my slave, my robot, my tool."

Naku stared, stood silent. "I will obey you," he said again.

"This place burns," spoke the Martian commander through the lips of Lumbo. "The ray-blasts are fiercer than the fires you know. The flame they began will destroy even tiles, even metals. But we will get away. I shall survive, with you for my slave, until more of my people — in space-ships —"

Neither he nor Naku heard the stealthy feat that had come up behind him. But now Lumbo's eyes, still holding Naku's, bulged almost from his head. His mouth fell open, but speech died in it.

His body drew up stiffly, his hands flung themselves out.

Through the center of his naked breast something came into view, like a serpent rising from a pool.

It was blood-dyed, keen, the point of one of the great blades with which some of the robots had been armed.

Lumbo crumpled down upon his face. And his slayer, who drew forth the weapon, was Arla.



Vwil's Farewell

NAKU, himself again, gazed at the girl with new wonder. Then he sprang around Lumbo's body, and caught her in his arms. And she wept as though her heart was smashed within her,

"I killed him, my brother — no, not my brother!"

"No, he was not your brother," agreed Naku, "but how did you know?"

"He spoke with the tongue of the Thunder Folk. I could not understand, but I knew that the enemy had gone into him. His heart was no longer Lumbo's heart. Oh, Naku, have I done well?"

"You have done well," said Naku, and comforted her. His eyes darted here and there. The fires were feeding everywhere, greater and wider and brighter. He drew her away from them, toward an unburnt quarter. As their flames followed, he led her farther and farther. They retreated toward the center, where lay the space-ship.

Arla recovered herself, and gazed about dauntlessly. Grief could harrow her, but not danger.

"This place burns, and all its devils with it," she ventured.

"And we too," replied Naku.

"But we have won," was her almost joyous rejoinder. "Our death will be a good one. Every one of the Thunder Folk gone —"

"No, not all!" exclaimed Naku, and sprang forward, ready to do battle with his fists, his only weapons. A gaunt, high-skulled figure hurried heavily toward then, a surviving Martian. But one claw-hand was lifted in truce.

"Is it you, Naku?" panted the anxious voice of Vwil. "Come, I can save you."

"How?" demanded Naku. "The fire is all around us — but wait, your chief said, when he spoke from my friend's body, that there was a way. Lead, but no treachery."

The three hurried to the space-ship and into it. Down a corridor Vwil led the way, then down another. They came to a central chamber, stacked high with cylindrical drums.

"This is all the fuel that is left," panted Vwil. "Bring it." He hoisted a container, Naku seized three, and Arla two more. They hurried down yet another passageway, and arrived at the far side of the ship. Here Vwil flung upward a great slide that revealed the open, and began to roll forth a little fish-shaped car, similar to the space ship itself in form but on a much smaller scale. It ran upon a little landing gear, and with Naku's muscular help, Vwil got it into the clear.

"It is a life-rocket, not dependent on the energy-broadcast machinery," he explained. "It will carry us away. Go back, Naku, for the rest of the rocket fuel, while I pour this into the tanks."

Naku obeyed, making several trips. At last Vwil motioned them into the tiny compartment that did service as cabin and control-chamber, and devoted himself to the controls. There was a roar, a shudder of the vessel.

IT was so. Vwil flew them high into the night air, then made a landing at the rim of the valley. They came out again, and looked down at the flaming structures that were once the stronghold of Earth's invaders and would-be conquerors.

"Will you slay this one, too?" whispered Arla to Naku as they emerged, but he shook his head.

"Vwil is kind. He alone seemed to be a friend when I was a prisoner. And he has now saved our lives, when he could have left us in the midst of that fire."

Vwil, too, came into the open.

"I have checked the equipment," he announced. "Emergency rations, water enough, and the fuel, though it would hardly stir the big ship, will carry this little one all the way home."

"Home to your star?" demanded Naku. "Is that where you go?"

"Where else?" smiled Vwil. "This world has hardly been hospitable."

"But you will bring back others to fight and kill us."

Vwil shook his domed head.

"No. I go to make a report to my people that your world is uninhabitable."

Naku looked his incomprehension, and Vwil elaborated:

"My commander used to say harsh things about my soft weakness. He scorned me for being merciful. Perhaps he was right — but he is dead, and I alone am left. My judgment must suffice. And I want nothing else to do with you men."

"We fight hard," agreed Naku.

"I am not even sure that we would win a permanent victory over you," went on Vwil. "You might be defeated temporarily, then rally and wipe us out. And we of my world are not seeking to die; we are seeking to live."

Naku felt a sudden burst of warm generosity.

"Vwil," he said, "your kindness counts for something. Perhaps we can live in peace, if we make every effort —"

"No, my friend," broke in Vwil. "You are wrong. You and I might live as neighbors and comrades. But my people are greedy, and yours are stubborn. There could be only war between them. It is better that we keep our ways separate."

He put out his hand, and Naku took it and shook it. Arla, who had understood none of Vwil's talk, did the same.

"And now I will enter my craft," finished Vwil. "I will give you time to get well away from the blast of the rockets. Good-by.

Vwil got into the life-rocket and closed the door. Naku and Arla walked briskly away, far along the rim of the valley. As they did so, they heard the roar of the take-off behind them, and turned to see. But Vwil was no more than a comet in the upper sky, seeming to slide away between the stars.

The two had time to look at each other and smile. It seemed to them that nothing would ever be exciting again, except each other.

"Rrau, the war chief of my people, is dead," said Naku. "Ipsar, the priest, is dead. I am young, but probably I shall rule what is left of us."

"Do your men take more than one wife?" asked Arla, and Naku shook his head. "One man takes one woman. Come with me, Arla. We shall reach home by morning, and I shall send a messenger to your tribe, with news and offers of friendship. After these dangers, men may learn to live at peace."

VWIL, afar in his lonely little ship, glanced back once. A rearward port showed him the globe of Earth, already falling thousands of miles behind.

"It is a beautiful place, and rich," he sighed to himself, "but I may be forgiven for lying to my people about it. No riches are worth pain and cruelty. We need more room, more food, more water — we shall find some other planet, deserted and wanted by no one. It will be strange if we Martians cannot make of such a place what we want it to be."