The mysterious woman who attacked Sanpeita was sitting behind Sanpeita the next day. In fact, she was a classmate, "Kurosaki Ryoko", who had never been to school since she entered school. Sanpeita is surprised and angry, but his classmates accept Ryoko. On the other hand, Izumi, who believes that Kemeko is the reason Sanpeita started to go crazy, challenges Kemeko to a swimming match...