Complete all of the following from a fresh save file:

• Main Story
• 'Most Wanted' Side Missions
• Dark Knight System
• Database (Case Files, Character Profiles, Audio Files, and Gotham Intel)
• Enigma Data Handlers, Network Towers, and the secret Riddler Trophy

If you are missing any Dark Knight challenges, you may start a NG+ cycle. If this happens, the run ends when you finish all the challenges and there is no hit probability i.e. you must finish whatever encounter you are in.