The Justice League have been constructing thier new base in orbit called the Watchtower. During testing of a teleportation system at the Hall of Justice, they are alerted by appearance of Lex Luthor. But on closer inspection and interrogation,they find out that he's from an alternate universe called Earth 3, where heroes of earth are a villainous authoritarian organization called the Crime Syndicate and the villains of earth are heroes of Earth 3. Luthor Jr asks for the help in saving thier world from thier oppression. The Justice League agree, despite Batman's disagreement. Meanwhile on Earth 3, the Crime Syndicate is in hunt of Luthor Jr as he had stolen a valuable piece of equipment for a powerful weapon being built. While the team face the challenge on thier own, Owlman has his own plans concerning the multiverse and the 'threats' to his plans that Luthor intends to bring in.
