The Anti-Monitor (the Monitor's evil counterpart) is released in the DC Multiverse and begins to destroy the different Earths that compose it. The Monitor attempts to recruit heroes from across the Multiverse, but is murdered.

Until now, the Justice League has been a loose association of superpowered individuals. But when they are swept away to Warworld, a place of unending brutal gladiatorial combat, Batman, Superman, Wonder Woman and the others must somehow unite to form an unbeatable resistance able to lead an entire planet to freedom.

Kara, devastated by the loss of Krypton, struggles to adjust to her new life on Earth. Superman mentors her. Meanwhile, she must contend with a mysterious group called the Dark Circle who searches for a powerful weapon held in the Academy's vault.

Recently discharged Marine sniper John Stewart is at a crossroads in his life, one which is only complicated by receiving an extraterrestrial ring which grants him the powers of the Green Lantern of Earth.

The Justice Society of America, a group of heroes aiding the allies in World War 2, acquire an ally from the future who sends them on an adventure that changes history.