Chizuru has left her teaching job to become a married woman, while Isejima has graduated and works for a security company. Although the two were once teacher and student, they made a one-time mistake. A few years later, they meet again by chance when Chizuru moves in next door to Isejima. Although they hide their shock, memories of the past come back to them and they begin to think of each other as the opposite sex. Their relationship, which was once that of teacher and student, has once again forged a forbidden relationship as that of a married woman and a young man...