It's school festival day and Min Hyuk is busy dancing and singing. However, it is not the stage but a toilet that binds his destiny. He is bewitched by a daring high school girl, Mi Hyun, who comes into the men's room because the women's room is full. From that day on, Min Hyuk woos her, escorts her home at night, stuffs her locker with roses, and clears passages for her in the morning after a snowfall. For all his efforts, he doesn't get much more than a tender glance from Mi Hyun. When she suddenly vanishes, "Sorry" is the only word she leaves behind.