After ten years since graduation, finally there was a class reunion, especially with the participation of the former homeroom teacher - the person whom the former student Saeko had once confessed her feelings to, but failed. That day, both Saeko and her current husband attended the reunion because her current husband was also a former classmate from high school. While he was chatting happily with his close friend, his wife was suddenly called by her boss about a work emergency. This made him rush to the company immediately to work overtime until the next morning to meet the deadline, leaving his wife and the party behind. As the reunion was coming to an end, Saeko was also feeling dizzy from drinking too much, so the former homeroom teacher took her to rest in a nearby hotel. At that moment, emotions surged, and he expressed his regret for rejecting her confession in the past, and he wanted to have a physical relationship with her for the first and last time to make up for his regret. Throughout that night until the next morning, their partying did not stop...