Fly High (2006)

(Korean with English subtitles) Min-hyuk would never have guessed that he would meet the girl of his dreams, the bubbly Mi-hyun, in the men's room during the school festival. From that day on, Min-hyuk does his best to woo - escorting her home at night, stuffing her locker with roses...Despite all his efforts, Mi-hyun suddenly vanishes one day and "sorry" is the only word she leaves behind.