His nephew, Naoyuki, is staying with his aunt Eriko, who has been Ke'ai of him since he was a child, and before he knows it, he has become aware of her as a member of the opposite sex, which leads to him acting awkwardly around her. On the other hand, Eriko is fond of Naoyuki, and makes advances on her at every opportunity. One day, when Eriko comes into his room and presses herself against him, Naoyuki becomes tense and excited, causing his crotch to swell. Sensitively sensing this, Eriko smiles and takes his large, erect penis into her mouth...