Nearly a year into her marriage, Yuri enjoys a happy home and gets along well with her adult stepson Yuichi. Yet her sexually indifferent husband leaves her secretly aching for physical affection. When he is transferred away for work, Yuri and Yuichi begin living alone together. At first everything seems normal, but Yuichi gradually moves closer, touching her more often and with increasing boldness. His advances soon become openly sexual, and he repeatedly creampies the lonely stepmother while promising to give her the child she desires.