Kaori is a 43-year-old housewife. She has been married to her husband for 15 years, who is devoted to his work. Although she fell in love with him because he was honest and straightforward, she now finds herself frustrated by his inflexibility. Knowing her husband's character so well, she is unable to be selfish, and has decided to have an affair in order to vent her desires. Kaori says that sex with her beloved husband feels the best, but today she finally experiences the pleasure of another man's penis for the first time...