Mirei, a mother who decided to stay at her daughter's place for a Tokyo sightseeing trip, noticed her daughter's mood shift after discussing the marriage and pregnancy of her childhood friend. According to her son-in-law, their marriage was good, but they lacked intimacy at night. Mirei kept her concerns to herself, understanding it was their personal matter. After a bath, she accidentally witnessed her son-in-law masturbating with her underwear. Feeling sorry for him, as he wasn't her real daughter's husband, she relieved him through oral sex. Late at night, while still troubled by the earlier incident, her son-in-law suddenly embraced her. Despite her reluctance, Mirei's body responded to his aggressive actions, awakening her long-dormant desires and plunging her into a rare pleasure.
