NTRH-015 Although she knew it was wrong, she was attracted to her son's homeroom teacher, Mr. Natsume, and they had many secret meetings. - Natsume Saiharu

Natsume chose to continue teaching even after getting married. However, the life of a teacher is already busy. Balancing work and family life is difficult, and the relationship between the couple has already cooled. Meanwhile, she visits the home of one of her students who has stopped going to school. The father, who is her guardian, is conflicted... The two, both feeling lonely, are drawn to each other, and even though they know it's wrong, they become immersed in a messy affair from which there is no turning back.