Black Mask's Blackgate Riot

On Christmas Eve, a Code 10 riot, instigated by Black Mask and his Henchmen, broke out at Blackgate Prison.

Prelude
On Christmas Eve, the serial killer, Julian Gregory Day, also known as the Calendar Man, was scheduled to face execution for his mass murders, with GPCD Commissioner Gillian B. Loeb overseeing the execution. While attending a press release on the event, Loeb dismissed further questions after one of the reporters implied it was Batman and not the GCPD who was responsible for Day's arrest.

After torturing Warden Joseph, and threatening his family, Black Mask forced him to make security lax in order to execute a prison riot inside the prison. After Black Mask and several of his men, including Killer Croc, broke into the prison, a dispatch was issued requesting backup. Loeb and the news crew were taken hostage during the riot. Bruce Wayne, overhears the dispatch and enters Blackgate to quell the riot.

The Riot
Upon arrival, Batman deduces the entry point of Black Mask and his men was a damaged entrance. Batman saves Warden Joseph from being brutally killed by some of Black Mask's Henchmen and then defends himself from a panic-stricken Joseph.