Haruka, the badminton club advisor, was having an affair with her colleague Ishida. Although she started dating without knowing he had a family, even after finding out, the relationship dragged on... Haruka had become a convenient woman. One day, a student named Yoshii witnessed this 'relationship that must not be known to anyone'. Upon learning that his favorite Haruka was having an affair, Yoshii began to coerce her into a physical relationship by using it as blackmail.
