High school student minori is a diligent girl. One day, while practicing alone on the rooftop, she catches her classmate okuro committing a crime and admonishes him. Their homeroom teacher takamoto appears and also scolds minori, but okuro has been blackmailing female students and providing them to takamoto in exchange for better grades. Seeing an opportunity, the two target minori, inviting her under the pretense of discussing her future, only to assault her...