Momoko married a man with a stepchild. Although she has a good relationship with her husband, it was difficult for her to open up to her son Naoki, and the relationship was awkward. Worried about her, her husband plans a family trip for her, but... Naoki actually saw her as a woman, not her mother. Unable to suppress her desire to see her defenseless appearance, she finally ends up having sex at night. A shock that violently penetrates deep into her vagina and a powerful piston that never ends. Momoko's body is in the best sex with Naoki, which she has never felt with her husband.