Isabel Duncan, a scientist at the Great Ape Language Lab, doesn't understand people, but apes she gets — especially the bonobos Sam, Bonzi, Lola, Mbongo, Jelani, and Makena, who are capable of reason and communication through American Sign Language. Isabel feels more comfortable in their world than she's ever felt among humans — until she meets John Thigpen, a very married reporter writing a human interest feature. But when an explosion rocks the lab, John's piece turns into the story of a lifetime — and Isabel must connect with her own kind to save her family of apes from a new form of human exploitation.