Miho Yamaguchi, a 50-year-old housewife from Shinagawa Ward, has been married for 22 years. With zero cheating experience and sex with her husband only during New Year and Obon, she has satisfied her daily desires through masturbation. But today is a special day. Determined to forget about her husband and experience the most intense, mind-blowing sex she's never had before, she's fully prepared and ready to go.