Nanako, a stepmother, is troubled by her husband's relationship with her stepson, Masashi. Worried about him not coming out of his room because he is studying for exams, she goes to check on him... and finds him sleeping with his erect penis exposed. Nanako can't resist Masashi's impressive cock, and starts to jerk him off... Then, when Masashi wakes up, she begs him to cum. But Masashi is not satisfied with a single ejaculation, and when he approaches her while showing off his erect penis, Nanako is fired up and can't refuse...