Tsugumi Akari plays a married woman named Rie who plans a two-night, three-day hot spring trip with her husband Kengo and his younger brother Yuji. This destination holds special memories, as it was a place Rie and Kengo once visited with their late parents. However, the inn's bath rotates between men's and women's use, and Rie, unaware of the schedule, enters during men's time and runs into Yuji. Shocked by unexpectedly seeing her naked for the first time, Yuji is overwhelmed by uncontrollable desire and forcefully advances on her, leading to an unforeseen and intense encounter.