Yuka, a housewife, moves in with her husband's father, Tokuzou, who needs her care. Of course, Yuka has no objections to caring for her father-in-law, who raised her husband Toru on his own, but... In her daily life, the kind-hearted Yuka is taken advantage of by the perverted old man Tokuzou. She is confused when he uses her for sexual purposes under the guise of caring for her, but gradually she becomes addicted to the pleasure and surrenders to it.