A story of two pairs of mother and child. Tatsuo Kuroyanagi, a boy who goes to a university in Tokyo and lives alone. Because of the renovation of the house, the brothers of Yohei Takashima and Yasuhiro Takashima, and the aunt Ao Takashima are the house of Misako Kuroyanagi. In other words, he lives in Tatsuo's parents' house. One day, Tatsuo took her home as originally planned, but she couldn't help sexually arousing her mother, leaving her behind and having sexual intercourse many times after an obscene delusion. It ends up. At the same time, Yasuhiro also becomes unbearable and has sexual intercourse with his mother.