In order to take care of her nephew Kosuke, who is depressed after losing his mother, Aunt Chisato decides to let him stay at her house for a while. However, Chisato secretly sees Kosuke as a man, and every day she casually seduces him, which stimulates his crotch intensely. One night, Chisato washes Kosuke's back... Kosuke can't contain his excitement at the sight of his aunt's naked body. As soon as Chisato sees his erect crotch, she smiles and starts sucking his cock...