The novel opens as Eva wakes up in a hospital bed, paralyzed. Her mother assures her she will be fine, that the doctors will gradually reduce the paralysis. Eva guesses that her face has been badly scarred, but when she looks in a mirror, she sees the face of a chimpanzee. An experimental procedure has been used to transplant Eva's "neuron memory" into Kelly, a young chimp from her father's research facility.
Eva learns to adapt to her new body, using a keyboard to simulate her voice. She has dreams of a forest she has never seen - that Kelly has never seen either - and imagines it comes from the chimpanzee unconscious. She realizes that she must accept the chimpanzee part of herself, which is easier for her as she has grown up with her father's chimps.
The cost of the procedure has been met by a media company in return for broadcast rights. Eva is a big hit with the public and her family has to cope with massive media interest. The power of the 'shaper' companies is immense in a world where many people spend all day at home. 'Shaper' technology is a cross between television and virtual reality.
Eva spends most of her time with humans, even going to school, but also spends time in the Reserve, where she learns to adapt to the chimpanzee social group. Her human understanding helps her to manipulate some of the situations and she becomes accepted by the others. One particularly intelligent chimp, Sniff, is intrigued by her.
With the introduction of enthusiastic animal rights advocate Grog Kennedy the novel takes another turn. He convinces Eva that for the sake of the species the chimpanzees must return to the wild. Not only do they belong there, but Grog believes the human race is running out of steam and will before long no longer bother to care for animals in captivity. At this stage there are only small pockets of wilderness left, and most species have died out.
Grog and Eva devise an ingenious plan to get the chimps to the island of St. Hilaire near Madagascar where Eva and Sniff lead the others in an escape. Her human knowledge is necessary to help the chimps learn the skills necessary to survive, which means that she must cut herself off from other humans. The novel ends twenty-four years later when Eva is near death, the human race is in decline and Eva imagines a future in which the descendants of her band of chimpanzees become the new dominant race.