White Day: A Labyrinth Named School (화이트데이: 학교라는 이름의 미궁). The story of a young man's trip into school at the dead of night to deliver some candy in preparation for the Eastern Holiday of the same name, White Day (the South Korean/Japanese equivalent of Valentine's Day) to 'So-yeong', a girl at school he likes, and to return the diary she left behind. Finding himself locked up soon after entering, escaping the school now becomes a nightmare...
even though it's released in 2001, I still think this deserve to get 10/10.