My father-in-law lives with his son and his wife. His son's wife, Yuri, is kind, beautiful, and hardworking, and he is constantly relying on her for things like taking him to and from the hospital. Ever since he found out that his son's wife secretly masturbates in between housework, my father-in-law has been Kokoro, but his crotch is hot. His son, who seems to be unable to satisfy his devoted wife in the sex life, feels sorry for her and one day does the forbidden act...!