Usa, a first-year in high school, is moving into the Kawai Complex after his parents have to move because of work. It's an old building, but Usa likes what he sees, until he finds out that he will be living in the same room as a perverted masochist (Shiro).

After being told by Sayaka that he can get Ritsu to open up, Usa decides to play dumb and go on the attack, convinced that he can save Ritsu from her loneliness. Soon after, he's passing by a book store when he witnesses Ritsu talking happily to friends from middle school.