During the battle of the House of Brainiac, Lex Luthor's memories were wiped clean... but now, after the events of DC All-In Special #1, the world needs Lex to remember his past. There is a key piece of information in Lex's lost memories that could unlock an epic mystery that plagues Superman and the Justice League! But what if Lex doesn't want to remember? Would Superman sacrifice Lex's newfound peace to solve a secret, even if it means the return of Superman's fiercest rival?