Feeling sorry for Shizuka, whose mother had to live alone after her father was hospitalized due to illness, her daughter and her husband Atsushi suggested that the three of them live together and invited Shizuka to their home. When Shizuka passed by the daughter and son-in-law's bedroom, she caught a glimpse of the couple's unsatisfied sex life. The next day, Shizuka tried to mediate between the two, but her husband Atsushi was Kokoro by his mother-in-law's kind consideration and her voluptuous body and attacked her without thinking... It seemed like a one-time mistake, but when Atsushi heard Shizuka masturbating while muttering his name, he headed back to the bedroom where Shizuka was waiting...