The father-in-law, who lives with his son's wife Non, is always looking after her, being kind, beautiful and hardworking. Ever since he witnessed his son's wife secretly masturbating between housework, as if it were her daily routine, the father-in-law has been feeling hot between his legs, even though it has pained Kokoro. His son, however, seems unable to satisfy his devoted wife in the sex life. Feeling sorry for his son's wife, the father-in-law can't help but do the forbidden act...!