While visiting her husband's family home, Sumire finds herself caught in an unexpected situation on the night before returning to Tokyo. Her father-in-law, who has long been dissatisfied with his son's wife, suddenly makes a bold proposition on the eve of her departure. Initially refusing, Sumire gradually finds her resolve weakening under his persistent advances, slowly swallowing down her resistance. In the end, she gives in to temptation. A story of one fateful night, capturing the father-in-law's determined desire and Sumire's inner emotional turmoil.