Created in a biological science lab, Charlie is a half human, half chimpanzee hybrid known as a "Humanzee." Raised by his adoptive human parents, Charlie is now 15 and starting high school. There he meets Lucy, a clever loner who becomes his first-ever friend. But his "normal" life is shattered when the animal rights extremists who freed his mother from the lab fifteen years ago reemerge as terrorists bent on kidnapping Charlie at all costs. Half-human, half-chimpanzee Charlie's birth mother Eva is dead-but her startling last message could change everything. Even as Charlie and his friends struggle with the possible existence of another humanzee, a fateful encounter forces them to accept the truth... And now Charlie faces his greatest challenge yet!