The player begins as a second year student at the Shin Mikado Academy. He recently went to the Otherworld with his sister Chiyo where he encountered a daemon who granted him a power called the Authority of Vanity. Unfortunately, one of the side effects of going to the Otherworld and becoming a Pactbearer (at least in the protagonist's case) is amnesia so he has no idea what's going on. Back in the real world things aren't running so smoothly, as Shin Mikado Academy is surrounded by a mysterious barrier while a mist that leads to madness engulfs several of the floors of academic buildings. Oh, and a bunch of students keep ending up dead.