Ayumi, a married woman, feels aching due to a lack of sex with her husband. Although she relieves her sexual desire by masturbating, she cannot relieve her loneliness. Meanwhile, her stepson sees her erect penis. She blurts out, "Shall I help you pull it out?" and the two begin a forbidden relationship. Ayumi is fascinated by his young, perky body, which is different from her husband's, and before long she discovers the pleasure of having semen ejaculated deep inside her vagina...