While his wife is away for her hometown childbirth, Yuna, his sister-in-law, comes to stay at the house. Keiji, struggling with unfamiliar household chores, gladly accepts Yuna's visit, unaware of her true intentions toward him. As she cleans, she constantly sends him seductive glances, flashing glimpses of her tanned cleavage and sleek, shapely legs. Each time, Keiji can't help but react. Trying to hide his arousal, Yuna softly whispers, "Right now, she's not here—everything's fine. Nobody will ever find out," luring him deeper into temptation.