An expedition to a mysterious expanse of unexplored Africa unexpectedly brings primatologist Peter Elliot and Travicom Project Supervisor Karen Ross to a place where human greed and the laws of nature have gone berserk. Unlikely partners, Peter is the guardian of Amy, a remarkable gorilla he wants to return to the wild, while Karen has been sent inland to retrieve rare diamonds needed for new communications technology. In a search for the legendary lost city of Zinj and its fabled diamonds, they are accompanied by their guide Monroe Kelly, Peter's colleague Richard and philanthropist Herkermer Homolka. The expedition discovers that in the Congo, they are the endangered species.