Hisashi is asked by his younger sister Kyoka to take care of his nephew Kazuaki. My nephew is cute, who responds in a beginner's mind just by giving a glimpse of sex appeal, and to kill time, he ends up in while taking a bath... Despite Kazuaki being confused, Hisae innocently plays with her cock, which is full of excitement and tension. For Kazuaki, who doesn't know women, it is a pleasure he has never felt before, and at Hisae's mercy, he is finally led to ejaculation. However, his frustrated desires are unknown to him...