Hidden cameras reveal the truth between a man who only wants to fuck and an exceptionally sincere 22-year-old adult student. The devoted girlfriend insists she has no interest in cheating, grows jealous when Koichi mentions a singles bar, and admits her masochistic desire to be slapped—but only by him. Clinging to his arm and melting when he strokes her head, she falls for him so deeply that she cannot hold back her orgasms. A beautiful woman who would never sell sex for any amount of money has her feelings exploited until she gradually gives in to sex.