What Made Pre-Flashpoint Superman Come Out Of Hiding

So the short explanation is… this version of Superman and Lois Lane somehow made it out of the Flashpoint Paradox event and are living in the New 52 continuity. When the New 52 Superman died, Pre-Flashpoint Superman decides to come out of hiding to prevent Lex Luthor from tarnishing the Superman name.

From – Action Comincs Vol. 1 #957