Mitsuhiko, a nephew staying with his aunt Ai, tells Ai that he wants to live alone after getting a job. However, Ai, who wants to keep Mitsuhiko, asks Yamane, a business partner, for advice... One day, Mitsuhiko notices the moans coming from Ai's bedroom. When he peeks 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 to his room and starts playing with his rock-hard penis...