A story of two pairs of mothers and sons. Tatsuo Machimura, a son who lives alone while attending university in the Tokyo metropolitan area, has his uncles Yohhei Yuki and Yasuhiro Yuki, along with their aunt Natsumi Yuki, staying at his mother Anna Machimura's house for home renovations. In other words, they are living at Tatsuo's parental home. One day, Tatsuo, as originally planned, returns home with his girlfriend but cannot suppress his sexual arousal towards his mother, leaving his girlfriend aside and engaging in sexual intercourse multiple times due to lewd fantasies. Around the same time, Yasuhiro also can't hold back and has sex with his own mother. Moreover, the sons end up witnessing each other's incestuous acts.
