Over 100 people have been with her. In stark contrast to her sexually promiscuous school days, Kasumi Amamiya has been devoted to her boyfriend since she entered the workforce. She dated her boss, a serious man, for three years and finally got married last year. On a trip to celebrate her first wedding anniversary, she meets a college classmate in a hot spring resort in Yamanashi. "I never wanted to see these guys again..." They were her classmates from the sex club she belonged to. Kasumi swore she would never give in to them, but old memories gradually started to come back to her...