A pretty, young Alpha technician dies a horrible and unexplained death. Dr. Russell's experiments reveal that one of the crew is possessed of paranormal mental powers and is trying to take control of Moonbase Alpha....

Everyone on Moonbase is electrified by the arrival of a spaceship from earth. Everyone, that is, except Commander Koenig. Where the others see long-lost friends and relatives, he sees hideous aliens, bent on taking over the Moonbase...