In an alternate reality, the Joker has destroyed Metropolis and has tricked Superman into killing Lois Lane and his unborn son. In retaliation, Superman murders the Joker in front of Batman in a fit of rage and establishes a new world order. A battle ensues between the forces of Superman's Regime and those allied with Batman's Insurgency. The Insurgency discovers the Justice League's universe where the Joker's plan did not succeed and transports several of its super heroes (Wonder Woman, Aquaman, Green Arrow, and Green Lantern, with Batman and Joker being caught up in the transfer by accident) to theirs in order to help them defeat the Regime.
