Reiko Kobayakawa, a housewife entering her sixth year of marriage, struggles with a sexless relationship as her husband is consumed by work. Emotionally and physically starved, she eventually begins having affairs with other men. One day, her father-in-law unexpectedly walks in on her having sex with another man in the couple's bedroom. Witnessing the shocking scene, he presents Reiko with a disturbing ultimatum: "You must remain completely naked whenever you're in my presence." This twisted agreement drastically alters the course of Reiko's life.