Dr. Donald Blake is in India as part of an American medical mission bringing aid and supplies to the Hindus during the Sino-Indian War. Suddenly the village is shelled by Red Chinese tanks; Don transforms into Thor and catches each of the shells fired toward the camp. He then disables the tanks, ties them together and hurls them back where they came from. To prevent further incursions, he seals up the mountain pass used by the invaders and calls up a thunderstorm to bog the army down in the mud. In Peking, Chairman Mao Tse-Tung orders his generals and scientists to devise a way to defeat Thor on pain of death. Chen Lu, a physicist dreaming of power and glory, has his own ambitious scheme. He exposes himself to an infinite amount of radiation (having earlier immunized himself to it—really) and emerges as the super-powered Radio-Active Man! He reports to the leaders and outlines his scheme for destroying Thor….
A week later, a Chinese submarine fires Radio-Active Man out of a torpedo tube toward New York. Reaching land he blinds witnesses with his glow and melt bullets fired at him. In Times Square he issues a public challenge to Thor to meet him in single combat. Thor does not appear, though, as Don Blake is in surgery, performing a crucial operation. As soon as the patient is out of danger, he changes to Thor and meets his challenger. To the Thunder God’s surprise however, Radio-Active Man uses his powers to deflect Thor’s hammer and withstand his thunderbolts (shot from Thor’s hands). When Thor threatens to defeat the villain with his bare hands, Radio-Active Man reveals that any damage to his body would cause him to detonate like an H-bomb. Instead, the foe uses his radioactive powers of hypnotism (it’s a comic book, okay?) to put Thor into a trance. Radio-Active Man orders the enthralled hero to throw away his hammer, which he does—into the far distance. The villain orders him to go and search for it; away from the hammer for sixty seconds he reverts to his identity as Don Blake and the hypnosis wears off. When Radio-Active Man comes looking for Thor, all he finds is a puny human, who throws him off the trail. Returning to his office, Don is informed by Jane Foster that Radio-Active Man is demanding the authorities help him find Thor or he will blow up the city. Don, annoying Jane with his unconcern, locks himself in his lab for several hours where he manages to convert his x-ray machine into an electronic scanner the show him his hammer at the bottom of the Hudson River (amazing what they teach in med school these days). Don drives out there and dives to the river bottom and transforms into Thor. Returning to face his enemy, he creates a tornado which blows Radio-Active Man back to Red China, where he explodes on landing.