John Cromartie visits the zoo with his girlfriend Josephine Lackett, and a dispute arises. Josephine confronts John about his atavistic views and suggests that he himself belongs in the London Zoo. Without hesitation, Cromartie writes a letter to the zoo management, his request is granted, and he soon moves into a spacious cage in the monkey house. His two neighbors, a chimpanzee and an orangutan, are far from thrilled and would love to tear their new roommate apart out of sheer jealousy, especially since people are lining up in front of his cage.