When Dr. Karol Noymann (John Carradine) is killed in an explosion, aliens inhabit his corpse and use it to communicate with his former colleague, Dr. Adam Penner (Philip Tonge), revealing to him that invisible aliens live on the moon. After this revelation, the aliens set out to wipe out humanity by making zombies from their corpses. To survive, Dr. Penner, his daughter (Jean Byron), Dr. John Lamont (Robert Hutton) and Maj. Bruce Jay (John Agar) all hide in a bunker.