Tatsuo Kozuki, a boy who goes to a university in Tokyo and lives alone. Due to the renovation of the house, the brothers of Yohei Fujishita and Yasuhiro Fujishita, and their aunt Rika Fujishita are the house of Hikari Kozuki. In other words, he lives in Tatsuo's parents' house. One day, Tatsuo went home with her as originally planned, but she could not forbid sexual excitement for her mother, and she was left behind and sexually acted many times after an obscene delusion. .. At the same time, Yasuhiro witnesses his mother, Rika, and Yo-Hey having sexual intercourse, and is jealous of the enviable relationship. Moreover, I also witness the mother and child incest of the Akatsuki family.