Ayumi Natsukawa had slept with 50 people during her wild college years, but after entering the workforce she devoted herself entirely to her serious boss. They dated for seven years and finally married last year. During their first-anniversary trip to a hot-spring town, she runs into former classmates from the college sex club she once belonged to. She never wanted to see them again and vows not to give in, but old memories gradually return. After holding out as long as she can through an all-night threesome, she is finally conquered by their huge cocks...