Ayano, a mother who was abandoned by her parents and grew up in a facility, dreamed of a happy life with three family members due to the circumstances, but she was hurt by the clash between her realistic husband, Keiji, and her son, Takayuki, who bets on dreams. .. Before getting married, Ayano is taught anal pleasures by her lover who grew up in the same facility and longed for her brother. Since then, I haven't forgotten the taste, and I've always started to have anal sex with my husband. Takayuki, who knew about the abnormal couple's activities, had more emotions than his mother for Ayano, and finally crossed the forbidden line.