Minami lives happily with her beloved husband and daughter, but it has become a habit of masturbating at night without any help. And it was the same with his son-in-law, Tsuyoshi, who spent days comforting himself by looking at her. Minami, who was fascinated by his huge cock, made his heart flutter and continued to seduce him every time. The son-in-law could not resist his mother-in-law's invitation. One day, the two of them exchanged tit-for-tat every day and night.