Multiple countries choose the same day to test out their newest weapons of mass destruction. Hovering over the United States of America is a new weapons platform, called "The Sky Fortress". After demonstrating the Sky Fortress' ability to neutralize incoming missiles, the orbit of the Sky Fortress begins to destabilize. On hand in their civilian identities are Superman and Wonder Woman, who respond to the crisis. While Superman stabilizes the Sky Fortress, Wonder Woman rescues the civilians, who were falling to their deaths. Inexplicably, the anti-missile cannon is torn from the Sky Fortress. Neither Superman nor Wonder Woman can tear themselves away, from rescue operations, to prevent the theft of the anti-missile cannon. The anti-missile cannon soars over Central City, as it zeroes in on the Wilmoth Skyscraper.
The anti-missile cannon attracts the attention of police forensics scientist, Barry Allen, who responds to the crisis, as the Flash. Before the anti-missile cannon can destroy the Wilmoth Skyscraper, the Flash manages to evacuate the entire building. Arriving on the scene, Wonder Woman keeps a second missile from striking the skyscraper. Superman and Wonder Woman destroy the anti-missile cannon. Convening with the Flash, Superman and Wonder Woman decided to call in the Justice League of America. A radio bulletin informs the team that weapons of mass destruction have also been stolen from Great Britain and the Soviet Union. Furthermore, giants of stone have appeared in Brazil, Japan, and Central City. The Justice League of America split into teams of three, to investigate the crisis.
Aquaman, the Green Arrow, and J'onn J'onzz, the Manhunter from Mars, find the stone giant standing, seemingly waiting, in Tokyo. Suddenly, a nuclear missile appears in the sky. J'onn J'onzz, the Manhunter from Mars attempts to use his Martian breath to blow the missile off course. The stone giant grabs the Martian Manhunter, and covers his face. Astonishingly, J'onn J'onzz, the Manhunter from Mars cannot physically touch the stone giant, despite being held fast in it's crushing grasp. The Green Arrow brings the warhead down. Aquaman discovers another stone giant, beneath the surface of the river, firing nuclear missiles at Tokyo. Aquaman grabs the warhead, and destroys the launcher. The stone giants get their hands on both Aquaman and the Green Arrow. Then, suddenly, the stone giants vanish.
Superman, Wonder Woman and the Atom find two stone giants standing in Brazil. A strange electrical discharge coats the city with a protective sheen. A corrosive rain begins to fall, threatening the entire city with destruction. Superman uses his heat vision to evaporate the rain, while Wonder Woman lassoes the weapon causing the rain. One of the stone giants stops Wonder Woman from destroying the weapon. The Atom scales Wonder Woman's Lasso of Truth to the weapon, and disables it. The stone giants get their hands on both Superman and the Atom. Then, suddenly, the stone giants vanish. The Batman, the Green Lantern and the Flash engage the stone giants, in Central City. The stone giants are setting off earthquakes with another weapon of mass destruction.
The Batman and the Flash attack the stone giants, while the Green Lantern destroys the weapon of mass destruction. The stone giants hold the Batman and the Flash in their inescapable grip. When the Green Lantern attacks them, the stone giants drop the Batman, and the Flash, to go after the Green Lantern. The stone giants overpower the Green Lantern, and steal his power ring. Then, the stone giants vanish. The stone giants all reappear on a parallel earth, separated from Earth-1 by a single minute. When both worlds detonated similar nuclear devices simultaneously, the explosion created a rift in the time-space continuum. Three cities on each Earth will soon occupy the same dimensional space at the same time, resulting in the destruction of both worlds.
Rather then move their own cities, the stone giants opted to destroy the Earth-1 cities instead, using weapons of mass destruction stolen on Earth-1. Due to exposure to cobalt radiation on their Earth, the stone giants gained the ability to affect the material world, while being completely intangible. All of this information is transmitted to the Green Lantern by his power ring, which then transports the Batman, the Flash, and the Green Lantern to the stone giant's Earth. While the Batman and the Flash battle the stone giants, the Green Lantern sets about to moving their cities. The stone giants, however, have armed their cities to self-destruct, as a failsafe against alien conquerors. The Batman and the Flash try to warn the Green Lantern, to no avail. The Green Lantern, though, opts not to move the three cities, instead moving the entire world back into it's proper place in dimensional space. The crisis averted, the Batman, the Flash and the Green Lantern return to Earth-1.