A rotund Russian spy Joseph Javorsky (Tor Johnson) is being chased through the Yucca Flats, Nevada Test Site by agents trying to get a briefcase full of secrets he possesses about the United States. As the chase ensues an Atomic bomb is detonated killing the agents but endowing Javorsky with burned skin, insanity and a homicidal drive. Javorsky is turned into a beast and roams the Nevada environs seeking people to kill. A State Ranger Douglas Mellor (Hank Radcliffe) discovers the presence of the beast and tracks him down but not before the beast traps a couple of small boys intent on making them his next victims.