Bound by fate, Riko and her husband are together, but she feels distant from her step-son Daisuke. Though happy with her loved one, 'Riko' harbors loneliness. She accidentally sees Daisuke masturbating in the bathroom changing room. Her heart races at the sight of his erect penis. 'Riko' impulsively rushes out of the bathroom and says, 'Use that for me!' thus proposing a forbidden relationship! Still a virgin, Daisuke awkwardly gropes her breasts and eagerly latches onto her vagina. 'Riko' can't help but find it adorable and, becoming lustful, accepts his erect penis, making him graduate from virginity with raw insemination! Taught sex step by step, Daisuke copulates with 'Riko' all over the house every day, repeating thrilling incest... Before long, 'Riko' gasps and begs her step-son, 'I want a baby!' pleading for internal ejaculation, deepening their unforgivable relationship!
