Married for 14 years, Shizuka Momoi lives a stable, happy life with her kind and considerate husband. They both work full-time and enjoy financial security, yet she harbors one quiet frustration—her husband's strict habit of always using condoms during sex. Shizuka feels deeply that the difference between protected and unprotected sex is immense: "Such a thin rubber barrier, thick rubber—there's a huge difference in sensation." One day, when her husband goes on a business trip, Shizuka decides to indulge in a one-time fling and downloads a dating app. To her shock, the man she matches with turns out to be the husband of her coworker. With time on their hands, they meet for drinks and conversation, which quickly escalates into a passionate affair. Experiencing unprotected sex for the first time in years, Shizuka's long-suppressed desires explode to the surface, pulling her into a whirlwind of intense, forbidden pleasure.