Aliens from a dying world plot to conquer earth by praying on man's superstitions. Bringing two dead scientists (Michael Rennie and Karin Dor) back to life, they use their knowledge to re-animate various earth monsters, including the werewolf Waldemar Daninsky, Frankenstein's monster (both played by Jacinto Molina), the mummy Tao-Tet, and the vampire Count de Meirhoff.