A man who has lost his wife. Recently, he has been feeling particularly lonely and, despite his age, has been indulging in solitary masturbation. Then, his son's wife, Miharu, appears to provide care, only to stumble upon his act of masturbation. Amidst the heavy atmosphere, Miharu hastily offers, "Father-in-law, if you'd like, may I assist you?" That statement becomes the catalyst, leading to a slippery slope of physical relations. Despite her surprise at her father-in-law's thicker and firmer penis compared to her husband's, for her, who has not been intimate with her husband for a long time, the pleasure she receives from her father-in-law makes her acutely aware of her womanhood...