mayu horisawa is a top student at a school in tokyo, excelling in both academics and athletics as a member of the sports club. one day, while practicing alone on the rooftop, she catches a delinquent student, kuro, using legal drugs and confronts him. suddenly, teacher nakata appears and scolds mayu, but it turns out that nakata is also a corrupt teacher. the two set their sights on mayu and, on the eve of summer vacation, lure her out under the pretense of discussing her future education and then kidnap her.