Captain Nathanial Adam oversees the launch of space shuttle Atlantis, from the mission control room. On hand to watch the launch are Ronald Raymond and Rick Matthews, the brother of Commander Connie Matthews, Atlantis' pilot. As soon as Atlantis attains orbit, a radiation surge blacks out it's power. With Atlantis in jeopardy, Raymond excuses himself to make the switch to Firestorm. Similarly, Adam exits the mission control room to adopt his guise as Captain Atom. En route into orbit, Captain Atom recalls his genesis. As Nathanial Adam, he had been making some last minute repairs to a satellite, on the launch pad. Attempting to retrieve a dropped wrench, Adam slipped into the satellite, and was launched into orbit. Due to a malfunction, the satellite's nuclear power core detonated. Instead of being killed, Adam's vaporized body reconstituted on the launch gantry, in possession of incredible nuclear powers. Captain Atom detects Firestorm's approach on Atlantis. Not immediately recognizing the young hero, Captain Atom fires upon him. Firestorm parries Captain Atom's nuclear blast with one of his own. Once the confusion between the two men has been cleared up, each tries to use their respective energy powers to jumpstart Atlantis. Inexplicably, each man's power fades before it can reach Atlantis. Onboard Atlantis, the crew are suddenly accosted by a bizarre stowaway. Calling himself "Rayburn", the strange man seems to fixate on Matthews.
Both Firestorm and Captain Atom detect unusually high radiation readings emanating from Atlantis. Leaving Captain Atom in orbit, Firestorm heads to Metropolis to garner aid. Converting the air molecules in the skies above Metropolis into a giant confetti replica of Superman's "S" shield, Firestorm draws the Man of Steel to him. After explaining the situation, Firestorm and Superman head for Atlantis. Unseen by Captain Atom, Rayburn phases out of Atlantis, with Matthews in his arms, and heads down to Earth. Captain Atom and Superman board Atlantis, discovering Matthews' abduction. While Superman carries Atlantis back down to Earth, Captain Atom heads back to Earth to rendezvous with Firestorm. Encountering Rayburn, Firestorm's powers cut out, and he begins to fall to Earth. Captain Atom catches Firestorm, but suddenly suffers the same power loss, as he descends to the ground. Superman discovers both men unconscious. A quick scan with his x-ray vision reveals that the atomic energies that fuel both men's powers are not compatible. Close proximity to one another could result in fatality. Superman separates Firestorm several hundred yards from Captain Atom. Rayburn takes Matthews to a nuclear reactor in Denver, Colorado. Rayburn's presence somehow initiates a meltdown of the reactor's core. Rayburn resolves the crisis by destroying the core. Firestorm reconstitutes the shattered fragments of the core into restraints for Rayburn.
The restraints fail to hold Rayburn for more than a few seconds. Angered by Firestorm's actions, Rayburn beats the living daylights out of Firestorm. Firestorm uses his nuclear restructuring powers to transform a fire hydrant into a cannon. Rayburn is undaunted by the attack, and presses his advantage over Firestorm. Captain Atom joins the fight, but fairs no better than Firestorm. Rayburn's power launches every manhole cover into the air, simply from Rayburn having touched ground. Captain Atom vaporizes the deadly projectiles. Rayburn again grabs Matthews and takes off. Superman and Firestorm intercept them. While Firestorm and Captain Atom occupy Rayburn, Superman heads off to confirm a hunch. When Superman returns he reveals that Rayburn is actually a S.T.A.R. Labs scientist named Sam Raybourne. Exposed to deadly levels of radiation, Raybourne was forced in to isolation, for the safety of other. Loneliness ate away at Raybourne, until the day his powers manifested, and he escaped his confinement. The truth revealed to him, Rayburn ceases all hostilities. As his power begins to consume him, Rayburn absorbs the very radiation he is emitting, to protect Matthews. Rayburn dies, vaporized by his own power. The thee heroes go their separate ways, with Captain Atom returning Matthews to Houston.