Ok, so it starts with Batman trying to nab an exiled crime kingpin called Doyle who's trying to sneak back into Gotham. Bats goes into his private plane and comes out with a stone tablet under his arm and strict instructions to Commissioner Gordon not to go after Doyle for one hour. Doyle even takes Gordon's car and paints it mauve, his fetish color. Why? Because Batman made a deal and he wants to be able to make deals with criminals in the future, so this one better be honored. And the deal was for a tablet with Kryptonian script on it, which Doyle apparently dug up near Smallville, because exiled crime kingpins need hobbies. Batman brings it to Superman who discovers it's a message from his mother Lara and talks about his twin brother Kor-El. But he knows he doesn't have a brother because Super-Infant had total recall, he would have remembered (not to mention all those times he went back in time to watch Krypton die).
JUST THEN, the Fortress of Solitude sounds a kryptonite alarm to tell Superman an asteroid glowing with kryptonite rays is approaching Earth. AND JUST THEN, he gets an angry call from the Justice League, with Green Arrow calling him a crumb and a creep. But why?