 During the test of a new weapon, a plutonium bomb, a plane crashes in the test area. Colonel Glen Manning fearing that someone may still be alive runs to the plane, but before he gets to the pilot, the bomb explodes and burns him over 90% of his body. He is then brought to the base hospital, but is not expected to survive the night. The next morning, Manning not only is still alive, but the burned tissue is completely healed. When his fiancee Carol Forrest arrives to visit she finds out that he as been moved as well as the physicians that have been working on him, Dr. Paul Coulter and Major Eric Lindstrom, M.D.. Through some checking on her own, Carol soon finds out where they are keeping Glen and is horrified to find out that the radiation has affected his cells and caused him to grow uncontrollably. The doctors search find a cure, but before they can administer it to him, he escapes and begins terrorizing Las Vegas. They they corner him, but after they inject him with the formula to stop his growth, Manning picks up the needle and spears Major Lindstrom, killing him instantly. He then picks up Carol and makes off with her taking her to Hoover Dam where he is cornered by the military. He comes to his senses long enough to let Carol go and as soon as that happens the military opens fire on him causing him to fall seemingly to his death in the Colorado River.