Minami lives happily with her beloved husband and her daughter, but it has become a habit to masturbate at night without any help. And so was her son-in-law, Tsuyoshi, who spent days comforting herself by looking into her. Minami, who was fascinated by his big cock, disturbs his heart every time and continues to seduce him. Her son-in-law couldn't resist the invitation of her mother-in-law, and one day the two of them devoured pleasure day and night.