 Martian invader, Mota (Gregory Gaye), attempts to conquer the Earth as Mars is worried about its use of new atomic technology.The Martians 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 American scientist, and former Nazi, Dr. Bryant (James Craven) into assisting him and hires some criminals to be his henchmen.