The plot involves aliens who come to Earth to stop humans who have developed the ultimate weapon — one that can explode the "particles" of sunlight — and the aliens try to conquer Earth by resurrecting corpses from a cemetery. Actors screw up their lines, night turns to day and back in a single scene, and the movie's top billing goes to an actor who died early in the filming (Bela Lugosi) and appears only in a couple of scenes at the beginning. Later in the film, Lugosi's character is doubled by a taller, younger, blonde-haired man (some say Wood's chiropractor) holding a cape over his face. The special effects consist of pie tins substituting for UFO's and multitudinous stock footage.
The movie has a "campish" or cult film popularity among those who appreciate hilariously bad motion pictures. Such appeal is heightened by quotable lines such as, "Inspector Clay is dead. Murdered. And somebody's responsible!"