The story of two pairs of mothers and sons. Tatsuo Takayama, a son who goes to a university in the city and lives alone. For home renovation, his cousin Yoshio Akiyoshi and aunt Akiyoshi Taeko are staying at his mother Koyoko Takayama's house—his childhood home. One day, Tatsuo returns home as planned but cannot suppress his sexual excitement towards his mother, leading to repeated intercourse and ejaculation inside her. Around the same time, Yoshio struggles with his desire for his mother Taeko's beautiful ass. He then witnesses the incestuous act between Koyoko and Tatsuo.
