Five years ago, Batman and an alien are being pursued by Gotham's Finest. Green Lantern saves Batman from the police and the two form an uneasy alliance in order to find the alien. They journey to Metropolis to confront Superman, another alien. He doesn't take well to being confronted by the two heroes, however.
Superman; Batman; Green Lantern [Hal Jordan]; Flash [Barry Allen]; Dr. Stone; Victor Stone; Mother Box; Parademons
Green Lantern calls his friend the Flash to help stop Superman as the alien continues to get the better of GL and Batman. The battle finally ends when the four heroes find common ground: their outlawed status and the Mother Box. The Mother Box then generates a boom tube that transports an army of parademons to Metropolis. Meanwhile, the Mother Box Dr. Stone is analyzing also comes alive, flooding the STAR Labs with destructive energy, which critically injures Victor Stone.