The narrative centers on 16-year-old Shingo Chiryu, who was beaten and hospitalized for a month by a morbidly obese girl after he rejected her naked confession. This incident caused Shingo to develop gynophobia, a fear of all women. Although Shingo attempts to conceal his phobia, the school nurse detects it and recommends that he join the boxing club. Shingo soon discovers, however, that every member of the club is female, the club's adviser is the school nurse, and one of the members, Haruka Nishiharu (who is now slim), is the same girl who had hospitalized him.