The Line of Duty

The Line Of Duty is a Most Wanted mission in Batman: Arkham Knight. Unlocked after apprehending Poison Ivy, it serves as a counterpart to another mission called Gotham on Fire. The Rioters serve as the main villains.

Plot
Batman was assigned by Aaron Cash that all the firefighters of Station 17 have been missing in Gotham. As Batman rescues the fire crew, he finds out that Firefly made a deal with Chief Raymond Underhill to put all three fire stations on fire. As Batman rescued the chief, Batman sends him to GCPD Building for his actions.

Trivia

 * All the Rioters in this mission are a mix between The Penguin's Henchmen and Two-Face's Gang.
 * For instance the first that is given in the GCPD by Aaron Cash has The Penguin's Henchmen, and the last to save Chief Raymond Underhill has Two-Face's Gang.