The villainous Dr. Kobras (Donald Pleasence) has found a golden Aztec mask with which he plans to use to control the minds of world leaders, starting with the Dutch ambassador's beautiful blond daughter Jane Dobson (Sydne Rome) who had translated the instructions on it for him. However, he fears the interference of the Pumaman, a legendary man-god sired by aliens and the protector of the mask whom he believes to be living in nearby London.
After somehow learning that the Pumaman is an American male living in London, Kobras' henchmen begin to test people matching these criteria by throwing them from high windows as only the Pumaman will be able to survive such a fall. Not only is Kobras looking for the Pumaman but so is a large, muscular and mysterious Indian named Vadinho (Miguel Angel Fuentes).
The Pumaman turns out to be mild-mannered young professor Tony Farms (Walter George Alton), an American paleontologist working at the British Museum who is thankfully gotten to first by Vadinho who turns out to be a mystic Aztec priest who knew Tony's physician father and confirms the initially unbelieving Tony’s status as the latest in a long line of Pumamen by defenestration, a three story fall that he, unlike Kobras' victims, easily survives thanks to his natural cat-like agility. Vadinho then gives Tony a magical golden belt that when worn gives him a poncho-caped sweatshirt and slacks-style superhero costume and further powers.
Pumaman ultimately defeats Kobras by making the helicopter in which the evil doctor is attempting to flee crash. Tony then decides to marry the no longer brainwashed Jane and start work on a new generation of Pumamen while Vadinho returns with the mask to his hidden temple in the Andes in an alien spacecraft.