Set in South Korea in 2001, players control Lee Hui-min, a new transfer student at a local high school who sneaks into the institution after hours to prepare a white day surprise for his crush, Han So-young. Upon entry, Hui-min becomes trapped and begins to encounter the supernatural. With the assistance of other students, Hui-min traverses the building, hiding from foes and using item micro-management to solve puzzles to progress through the school, in an attempt to leave the building before dawn.