Audio: Japanese Subtitles: English Source: R3 DVD A high-school girl named Kana suddenly commits suicide in a classroom one afternoon. Her friend, Anzu, who at the time hears Kana humming a strange song, is on hand to witness the tragic scene. And while the disturbing event leads to media speculation about bullying at the school, Anzu cannot shake that feeling that something might be going on. With the mysterious melody still fresh in her mind, she decides to investigate the mystery with her friends.