Father-in-law Kozo, upon retiring, began spending more time with his daughter-in-law, Keiko, during the day. He started noticing her in ways he never had before—her figure, the curves of her body, especially her alluring, seductive big ass that captivated his heart. One day, he caught sight of her vulnerable form and became aroused, secretly watching her. Then, he touched her. Forgetting his role as a father-in-law, he escalated into increasingly bold acts. Keiko tried to hide herself, yet she couldn't stop his hands from caressing her ripe, mature ass. Between father-in-law and daughter-in-law, a new relationship begins to bloom.