Arkham Asylum may have been decimated during A-DAY, but its legacy lives on. 
 
Bloody, broken, and beaten…but Batman has a mission.

When the terrorist organization known as THE RED CROWN took control of Mayor Nakano's personal security detail, only the Batman could protect Gotham's highest-ranking city official from certain death! But when the pair is thrust into the sewers below, a much more sinister threat lurks in the darkness. Better look sharp, Batman, because a hundred thousand eggs with a hundred thousand little monsters inside are about to hatch…and they look HUNGRY… And outside of the sewers, the city streets being overtaken by larger, (somehow even more) horrific creatures! Collects Detective Comics #1044-1046; Detective Comics 2021 Annual #1.