We lay at the top of the hill, gasping in the baking sun.... I was feeling all sorts of queer things. We were seeing something that no human being had ever seen our ancestors as living beings instead of as a bunch of fossilized bones.... "What are they, Char?" Weddy whispered, sort of awed herself. "They're human beings, Weddy. They're human beings, and we're the first modern humans ever to see any."
Char, Weddy and Nuell are excited over their discovery on this strange planet Pleisto, but also terrified, for the leader of their expedition, Professor Joher, has disappeared. Nuell and Weddy, his son and daughter, are concerned for his safety, while Char, his research assistant, feels not only worried, but responsible for all of them. He realizes that these prehistoric people may have carried off the professor and may even have killed him.
The three set out to find Professor Joher, and their search leads them through a frightening world where they must fight for their lives every day, against mastodons and jaguars as well as Pleisto's prehistoric inhabitants. They befriend a wounded hunter a man who is like their own ancestors from millions of years earlier and hope that he will lead them to the professor.
As their journey progresses, Char is thrilled to have the chance to study prehistoric humans so closely, but he is disturbed: by the violence of everyday life on Pleisto, by its uncomfortable similarity to life on earth and by his own feelings of competition and aggression. In an exciting climax, he learns about human courage and about love, generosity and cooperation as well.
James Lincoln Collier is a well-known, award-winning author of fiction and nonfiction for young people. With his brother Christopher, he wrote the Newbery Honor Book My Brother Sam Is Dead. He is also the author of Give Dad My Best, The Teddy Bear Habit, and Inside Jazz. Mr. Collier lives in New York City.