Hotaru is an honor student at a school in Tokyo, and is a serious student with a strong sense of justice. She serves as a member of the discipline committee, and plans to go on to a famous university after graduation. One day, Hotaru sees a delinquent student, Kawagoe, bullying her classmate, Meguro, and tells him off, saving Meguro. However, Kawagoe, enraged by Hotaru's actions, knocks her unconscious and leaves her confined to an empty classroom during winter break. And then, her well-rounded, honor student body is endlessly devoured by vulgar guys...