The story centers on Rosemary Cooke, who reflects on her unusual childhood. She grew up with a chimpanzee sister named Fern, who was part of an animal behavior study. When Rosemary was five, Fern was abruptly removed from the family, causing deep emotional trauma and a rift within the family. As Rosemary grows up, she grapples with the memories of Fern and the ethical implications of the experiment, leading her to uncover long-held family secrets and question her understanding of what it means to be human.

Author

Karen Joy fowler