Superman and the Flash find themselves on opposite sides when they become "super bounty hunters."
From their respective cities, Superman and the Flash race to the city of Rosemont, to investigate a downed alien spacecraft. Inexplicably, Superman arrives ahead of the Fastest Man Alive. Scanning the craft with his microscopic vision, Superman is shocked at what he sees. Suddenly the Man of Steel is caught in a vibratory beam, projected from outer space, that threatens to shake him violently apart. As the beam reaches the crash site, the alien craft explodes. The beam continues on into Rosemont, where the Flash is on hand to witness the town's populace being shunted into another dimension, as the beam sweeps over them. While Superman ushers the townsfolk to safety, the Flash uses his super-speed to set up a counter vibrational frequency that blocks the beam. Superman tracks the beam to it's origin point, an alien warship in Earth's orbit. Once again, Superman sweeps the ship with his microscopic vision, discovering the same uncanny truth. The alien ship's are composed of living cells, and are, in effect, alive. Back in Rosemont, the Flash runs afoul of a second beam from space. This one englobes him in a force bubble, that then carries him into orbit. The warship opens fire on a second alien vessel, also in Earth orbit. Superman blocks the shot. A view screen forms on the outer hull of the warship. Superman is ordered to stand down, then directed to behold the abducted Flash, rising towards the ship. Thus distracted by his friend's peril, Superman, too, is englobed in a force sphere. Both heroes are brought aboard the warship, and imprisoned in cells specifically designed to thwart their super-powers.
Superman and the Flash meet the commanders of the two alien ships, Islayn, of the Volkir, and Aylem, of the Zelkot. Islayn's sole intent in attacking the Earth was to destroy the Zelkot ship, and kill it's pilot, a revolutionary Zelkot, called Iylar. Due to a time lag in the Volkir sensors, they were unaware that their beam had failed, until almost half of Rosemont had been shunted into another dimension. The Volkir and the Zelkot have been at war for millennia. Neither side is particularly bothered by the collateral damage that occurs on other worlds, that are touched by their conflict. The two races were once one, but separated during a civil war. Neither side remembers the root cause of the conflict, but, nonetheless, continues the war. The Zelkot claim that all life on Earth evolved from the biological waste matter of their ship's exhaust, left behind during a visit to Earth. These same Zelkot migrated to Krypton, taming that world's unstable core, which postponed it's inevitable destruction for centuries. Tiring of the endless war, Aylem dispatched Iylar to Earth, with a plan to end the war once and for all. The Volkir, however, live for the glory of war, and have come to stop Iylar at all costs. Believing that Superman and the Flash are the only two beings on Earth who could possibly interfere with their respective strategies, Aylem activates mechanisms in their cells designed to kill them. The Flash's own vibrations strengthen the indestructible mesh composing his cage. As it begins to constrict around him, the Flash finds himself seconds away from being crushed to death.
Superman suggests using passive resistance to extricate himself from the cage. The Flash vibrates just enough to ease himself into the walls, eventually phasing his way free. The Flash strikes down Aylem, then shuts down the Q-Radiation killing Superman. Superman smashes out of his cage, and clocks Islayn. With the two alien commanders unconscious, Superman and the Flash find themselves surrounded by Aylem's crew. Holding the entire Earth hostage, the Flash is pressed into the Zelkot's service. Their man, Iylar is traveling forward in time, heading for the barrier that connects the future to the past. Iylar's mission is to stop the Volkir/Zelkot civil war before it can begin. To stop this from happening, the Volkir have planted several booby traps along the route. The Flash is instructed to journey through time, to protect Iylar. If Iylar fails for any reason, the Zelkot will destroy the Earth. The Flash runs fast enough to break the time barrier, and races to catch up with Iylar. Upon reaching the 25th century, the Flash runs into something that stops him dead in his tracks. Aylem's crew arrives on board the Zelkot vessel, weapons drawn. With their respective commanders unconscious, neither crew is willing to issue orders. The Volkir, however, decide that since the Zelkot forced the Flash to aid their cause, the Volkir will use Superman to thwart them. The Volkir explain to Superman that if their war with the Zelkot never starts, then the Zelkot will have never visited Krypton. Without the Zelkot maintaining the planet's stability, it will have been destroyed centuries before Superman was ever born. Unable to face the prospect of his own non-existence, Superman flies off to stop the Flash. The Scarlet Speedster, however, has already been stopped, in the 25th century, by his old nemesis, the Reverse Flash, Professor Zoom.