Hisae is asked by her younger sister Kyoka to take care of her nephew Kazuaki. Her nephew's innocent reaction to even the slightest hint of sex appeal is adorable, and she can't help but barge in on him while he's taking a bath to kill time... Kazuaki is confused, but Hisae innocently plays with his cock, which is throbbing with excitement and tension. For Kazuaki, who has never experienced a woman, this is a pleasure he has never felt before, and he is at Hisae's mercy until he finally ejaculates. However, Hisae's frustrated desire knows no bounds...