An endless army of shadow demons bent on the destruction of all reality swarms over our world and all parallel Earths! The only thing opposing them is the mightiest team of metahumans ever assembled. But not even the combined power of Superman, Batman, Wonder Woman, Green Lantern and all their fellow superheroes can slow down the onslaught of this invincible horde. What mysterious force is driving them? And how do the long-buried secrets of the Monitor and Supergirl threaten to crush our last defense?

Death is coming. Worse than death: oblivion. Not just for our Earth, but for everyone, everywhere, in every universe! Against this ultimate destruction, the mysterious Monitor has gathered the greatest team of Super Heroes ever assembled. But what can the combined might of Superman, Wonder Woman, Batman, The Flash, Green Lantern and hundreds of Super Heroes from multiple Earths even do to save all of reality from an unstoppable antimatter armageddon?!

A heroic version of Lex Luthor from an alternate universe appears to recruit the Justice League to help save his Earth from the Crime Syndicate, an evil version of the League. What ensues is the ultimate battle of good versus evil in a war that threatens both planets and, through a devious plan launched by Batman's counterpart Owlman, puts the balance of all existence in peril.

Now fully revealed as the ultimate threat to existence, the Anti-Monitor wages an unrelenting attack on the surviving Earths that struggle for survival in a pocket universe. One by one, these worlds and all their inhabitants are vaporized! On the planets that remain, even time itself is shattered, and heroes from the past join the Justice League and their rag-tag allies against the epitome of evil. But as they make their last stand, will the sacrifice of the superheroes be enough to save us all?