The story of two pairs of mothers and sons. Tatsuo Oshima, a son who goes to a university in the city and lives alone. For home renovation, his cousin Yoshio Mizukami and aunt Yukie Mizukami are staying at his mother Shinobu Oshima's house—essentially, Tatsuo's childhood home. One day, Tatsuo returns home as planned but cannot suppress his sexual arousal towards his mother, leading to multiple acts of intercourse and ejaculation inside her. Around the same time, Yoshio struggles with his own desires for his mother Yukie Mizukami's beauty. He then witnesses the incestuous acts between Shinobu and Tatsuo.
