Martian invader, Mota (Gregory Gaye), attempts to conquer the Earth as Mars is worried about its use of new nuclear technology. They consider that it would be much safer, and beneficial for both Earth and Mars, if the Martians were in charge. Mota, having been shot down by an experimental ray gun, blackmails Americans scientist, and former Nazism, Dr. Bryant (James Craven (American actor)) into assisting him and hires some criminals to be his henchmen.