 Revenge, jealousy and a rivalry between two doctors result in dastardly human experiments when James West comes upon a voodoo sacrificial killing. As West shoots his gun into the air to stop the ritual, the zombie-like participants turn and walk away. West is then attacked by a huge man named Tiny John, but as the agents shoots the man in the heart, Tiny John simply turns away and heads for the swamp. While the agents investigate further, they learn why the people are in a trance and discover the real reason behind the doctors  contempt for each other.