In the middle of Zero Hour, Superman goes to check on his home in Metropolis, and finds himself in an alternate timeline.

Entering the Daily Planet as Clark Kent to investigate, he grabs his wife Lois for a kiss, and gets slapped as a pervert. Realizing Clark Kent does not exist in this timeline, he goes back out to explore as Superman again. Almost immediately, he meets Metropolis' current protector, the Alpha Centurion, who is fighting a villainess named Bloody Mary. Though she tries to kill him, Mary also appears to be strangely attracted to the Centurion. The local police force arrives, the 100, along with Maggie Sawyer and Jim Harper. Superman aids in Bloody Mary's capture, and escorts the wounded Centurion back to his headquarters at what was formerly LexCorp Tower, where he rejuvenates his injuries in a healing liquid, the aquavitae. Centurion explains his origins to Superman, and shocks Superman by introducing him to his girlfriend... Lois Lane! After briefly discussing their differences, the two heroes return to the rest of the world to fight, in Zero Hour.