Yoka, the advisor for the badminton club, was having an affair with her colleague Ishida. Although she started dating him without knowing he had a family, even after finding out, their relationship continued… Yoka became a convenient woman. One day, this 'relationship that must not be known by anyone' was witnessed by a student, Yoshii. When Yoshii found out that his beloved Yoka was having an affair, he used this information to coerce her into a physical relationship.
