Current swimming instructor and young wife, "Mimi Mizuse," who teaches children how to swim at a Tokyo fitness club, makes her AV debut. Beloved by both students and parents for her maternal, gentle smile, Mrs. Mizuse is a popular figure. However, her true nature is that of a licentious married woman who finds daily masturbation necessary to satisfy her desires beyond her sex life with her husband. She reaches climax for the first time in her life experiencing the pleasure of another man's penis through an affair.