A story about two mothers and children. My son, Tatsuo Asamiya, who goes to a university in Tokyo and lives alone. Brothers Yohei and Yasuhiro Tanihara and their aunt Yuki Tanihara live with their mother, Ryoko Asamiya, due to the renovation of their house. In other words, he lives in Tatsuo's parents' house. One day, Tatsuo went home with her as originally planned, but he couldn't help but get sexually excited about his mother, and he ended up having sex over and over again at the end of his obscene delusions. . At the same time, Yasuhiro witnesses his own mother Yuki and Yohei having sex, and becomes jealous of their enviable relationship.