Prot is a patient at a mental hospital who claims to be from a far away planet. His psychiatrist tries to help him, only to begin to doubt his own explanations.
Test pilot Tuck Pendleton volunteers to test a special vessel for a miniaturization experiment. Accidentally injected into a neurotic hypochondriac, Jack Putter, Tuck must convince Jack to find his ex-girlfriend, Lydia Maxwell, to help him extract Tuck and his ship and re-enlarge them before his oxygen runs out.
Eight people embark on an expedition into the Congo, a mysterious expanse of unexplored Africa where human greed and the laws of nature have gone berserk. When the thrill-seekers -- some with ulterior motives -- stumble across a race of killer apes.
