You move into the dorms with your classmates today, they know you have the potential to be a Persona user, but you haven't been able to unlock it yet.

During the day, you and your dorm mates go to school at Gekkoukan High School together and hangout, but around midnight, it becomes the Dark Hour, and the school morphs into Tartarus, a 264 floors building that casts Shadows that will attack humanity. You joined your classmates who are apart of "SEES" to stop the shadows during the Dark Hour.

Persona 3 RPG