Rikiya Shoda is an engineer working for the Atomic Agency in Japan. One day, his wife Nanako returns home with a lost teenager called Ayu. A man, pretending to be the father, comes to get her back; Ayu keeps telling him that Rikiya and Nanako are her parents. Through this disruption, Rikiya suddenly starts remembering his youth as a revolutionary.

After 15-year-old Yasuko has her first orgasm with a teacher, she and her disillusioned group of friends decide to turn to prostitution to gain a better understanding of what emotions truly are.