Abandoned by her parents and raised in an institution, the mother, Ayano, dreamed of a happy life with her family of three. However, she was heartbroken by the conflicts between her practical husband, Keiji, and her son, Takayuki, who gambled on his dreams. Before marriage, Ayano, who had grown up in the same institution and admired her lover like an older brother, learned the pleasure of anal sex from him. Since then, she couldn't forget that sensation and always insisted on anal sex with her husband. Knowing about his parents' abnormal acts, Takayuki developed feelings for Ayano beyond those of a mother, ultimately crossing the forbidden line...
