Prior to his incarceration in Arkham State Hospital, the Riddler made a final plan with his followers to destroy Gotham City by assassinating the newly elected mayor Bella Reál, believing that corruption will never change for the better. Explosives were set at seven different points of Gotham's seawall to flood the city, with the intention of killing the mayor in the ensuing chaos.
By the time Batman learned of the plot, it was already in motion. As the streets of Gotham City were engulfed in a torrent of water, citizens like Selina Kyle fled to higher ground at Gotham Square Garden, where the Riddler's followers were confronted and defeated by Batman in their attempt to kill Bella Reál.
As a result of the disaster, Gotham was left in ruins, leading to the implementation of martial law in the city and the activation of the National Guard to assist in recovery efforts. Gotham Square Garden was used as a temporary evacuation center, with helicopters arriving at the complex to airlift injured Gothamites. Penguin, now boss of the Falcone Crime Syndicate, watched the scene from Iceberg, now his base of operations.
- The flooding of Gotham by the Riddler's plan heavily draws inspiration from the New 52 arc, "Dark City." It was written by Scott Snyder and Greg Capullo and was part of the Batman: Zero Year storyline.