When Dr. Ken Turner and his colleagues finally find half-human, half-chimpanzee hybrids in the dark jungles of the Congo, they think they are at the end of their long quest, but shady government agents have discovered the hybrids and plan to exploit them for military use. With the ruthless agents growing ever closer to realizing their goals, Dr. Turner and company must find a way to protect the creatures without destroying their careers and, for that matter, their very lives.