The Slavemaster from the stars arrives to reclaim his ship from the Justice League only to find that its key systems have been cannibalized to create Booster Gold's new armor. But the Slavemaster will stop at nothing to take back his technology, and he's got help: namely, Zan, Jayna and an entire team of morphing aliens!
As the terminally ill Firestorm's powers reassert themselves full blast, his elemental aspect returns to Earth to reclaim his human half. But when Raymond resists, Captain Atom and the Justice League must prevent the Nuclear Man and the Fire Elemental from destroying each other.
With Captain Atom missing and presumed dead, the team battles an unstoppable group of war-cyborgs bent on ousting the heroes from Mount Thunder. Meanwhile, the secret organization behind the paramilitary conspiracy gets ready to launch its metahuman army against the U.S. itself.