A Martian warship attacks the space shuttle Explorer. Firestorm, the Nuclear Man, and J'onn J'onzz, the Manhunter From Mars, ascend into space, to render aid. Unbeknownst to the two heroes, they are being observed by the Martian leader, the Marshall. The Martian Manhunter's strength proves insufficient to stop Explorer from falling into Earth's atmosphere. Firestorm, the Nuclear Man, uses his atomic restructuring powers to stop Explorer's descent. Firestorm, the Nuclear Man, accuses J'onn J'onzz, the Manhunter From Mars, of being a spy for the Martians.
Zatanna is appalled by the accusation, and is quick to set Firestorm, the Nuclear Man, straight. Zatanna reviews the events leading up to the current crisis. The United States military attempts to take the Hawkwoman, the Hawkman, and the Martian Manhunter into custody. Firestorm, the Nuclear Man, scares the military away. The President of the United States of America, Ronald Reagan, personally apologizes to Aquaman, for the attempted military takedown, of the alien members, of the Justice League of America.
Aquaman wonders why the most powerful members of the Justice League of America-The Flash, the Green Lantern, Superman, and Wonder Woman-have not responded to the crisis. Aquaman ponders the growing lack of commitment the membership has been showing to the Justice League of America. The Elongated Man teleports aboard the Justice League of America's satellite headquarters. The Elongated Man apprises Aquaman of the situation on the ground, as humanity prepares for the Martian invasion. The United Nations refuses to acquiesce to the Martians' ultimatum.
Firestorm, the Nuclear Man, is exuberant in his pride, joyfully commending Earth's decision to resist. The Elongated Man, soberingly, points out that a war of worlds has just been declared. It is not a moment for celebration. The Hawkman, on watch for the Martian fleet, reports in to Aquaman. Suddenly, the Martian fleet appears. The Martian fleet attacks the Justice League of America's satellite headquarters. The Martian fleet descends on Earth. The nations of the world mount an offense, that proves completely ineffectual against the Martians' defenses.
The Martian fleet decimates Earth's defenses. The Challenger, a robot scout, boards the satellite headquarters of the Justice League of America. Aquaman attacks the Challenger. The Green Arrow destroys the Challenger. The Red Tornado has been seriously injured, during the Martians' assault on the satellite. Still suspicious of J'onn J'onzz, the Manhunter From Mars, Firestorm, the Nuclear Man, goes in search of him. When the Challenger goes silent, the Marshall orders more ships to close in on the satellite.
Unbeknownst to the Marshall, his woman, Bel Juz, is the true architect of the Mars/Earth war. To protect herself from the Martian Manhunter, Bel Juz has done everything in her power to keep J'onn J'onzz, the Manhunter From Mars, from learning of her crimes. It is her machinations that have brought Mars and Earth to war. Firestorm, the Nuclear Man discovers the Martian Manhunter preparing to leave the satellite, in a shuttle. J'onn J'onzz, the Manhunter From Mars beats Firestorm, the Nuclear Man down, to keep him from pursuing him. The Martian Manhunter pilots the shuttle through the hull of the satellite, creating a massive breach. Explosive decompression threatens to sweep Firestorm, the Nuclear Man, out into space.