After leaving her teaching position to become a married woman, Chizuru, and Isejima, who graduated from school and works for a security company. Despite their former relationship as teacher and student, they had committed a one-time mistake. Several years later, through the chance of Chizuru moving next to Isejima, they unexpectedly reunite. Both, while trying to hide their turmoil, begin to recall past memories and start to perceive each other as members of the opposite sex. The relationship that was once <teacher and student> is now rebuilding as <married woman and young man> into a forbidden relationship...