Married to Shigeru for 16 years, Sumire lives a stable, happy life with her kind and considerate husband, both of them working full-time. Yet there's one lingering dissatisfaction—her husband's strict habit of always using a condom during sex. "That thin rubber... yet such a thick barrier. The pleasure is completely different with or without it," she thinks, deeply frustrated. One day, when her husband goes on a business trip, Sumire decides to indulge in a one-time fling and downloads a dating app. To her surprise, she matches with none other than the husband of her coworker. In an unexpectedly awkward situation, the two bond over drinks while passing the time, and before long, they cross the line. Experiencing the long-forgotten sensation of bareback sex, Sumire's suppressed desires erupt, pulling her into a whirlwind of new, overwhelming emotions.