Asahi lives with her kind husband Koichi and her father-in-law, Haruo. Haruo treats Asahi gently, often expressing his desire to see grandchildren soon. However, Asahi finds her married life with Koichi emotionally and physically unfulfilling. Noticing her dissatisfaction, Haruo takes advantage one morning after seeing Koichi off to work, assaulting Asahi. From that day on, whenever they are alone together, Haruo repeatedly forces himself on her in increasingly lewd acts. As this pattern continues, Asahi begins to awaken to pleasures she never experienced with Koichi, developing unexpected and conflicting emotions toward her father-in-law.