Mitsuhiko, the nephew of his aunt Ai, is staying with her and tells Ai that he wants to live on his own after getting a job. However, Ai, who wants to keep Mitsuhiko, goes to her business partner Yamane for advice... One day, Mitsuhiko hears erotic moans coming from Ai's bedroom. Peeking inside, he witnesses Ai having sex with Yamane. This makes Mitsuhiko aware of Ai, and he goes to his room to satisfy his still-excited penis. Then, as if on cue, Ai comes into his room and starts playing with his rock-hard penis...