After the death of her mother-in-law, Yui Hatano and her husband begin living with his father, forming a household of three. Since marriage, Yui has devoted herself to her husband's pleasure, always behaving as a submissive masochist. But one day, while caring for her father-in-law, she catches sight of his erect penis. Trapped in a paralyzed body, the father-in-law finds himself vulnerable as Yui's heart reaches a turning point, awakening to something new.