Batman / Superman: World's Finest (Batman / Superman: World's Finest #45)

Lex Luthor and the Joker have joined forces once again, but this uneasy alliance hinges on a crucial outcome: the final defeat of both Batman and Superman. Why else would the most brilliant criminal mind of our time and the Clown Prince of Crime team up? Well, the answer will surprise you... and them! Betrayal abounds, terror intensifies, and a major surprise is in store for the Dark Knight and the Man of Steel in part one of "The Merger".