Enigma Conundrum

Enigma Conundrum was a Gotham's Most-Wanted Side Mission in Batman: Arkham City.

Villain

 * The Riddler

Overview
Batman had to solve all 440 of the Riddler's challenges, which included both solving Riddler's signature riddles and collecting Riddler trophies throughout Arkham City. During the side mission, Batman could also make interrogate the Riddler's undercover informants to find the locations of both the answers to the various riddles and the Riddler trophies. After completing enough of Riddler's challenges, Batman could then use the Enigma Machine to solve a riddle and find the location of one of the hostages, as shown by Riddler. All the hostages, with the exception of the first one, are trapped inside rooms with deathtraps that Batman must overcome with the help of all the gadgets in his arsenal. At the end of each room, the hostage gives Batman a code that is actually a radio frequency that Batman can then use to help find the next hostage.

If Batman completes at least 400 of Riddler's challenges, he will then be able to find Riddler's hideout and take him down.