Eriko Miura, a MILF stepmother, becomes the mother of her new husband's college-aged son. Initially nervous, she finds comfort in his kindness and love, believing the three of them can build a happy family together. But one day, her stepson returns home in a foul mood. Worried, Eriko asks what’s wrong and learns he’s been dumped by his girlfriend—an utterly shocking revelation. When she discovers the reason, she’s stunned: her son had been aggressively pursuing her, having sex with her daily. Despite his mild appearance, he harbors an intense, insatiable sexual desire. A few days later, unable to suppress his urges, he finally reaches out to Eriko. With his young, virile body, he thrusts relentlessly, overwhelming her with a devastating mix of shock and overwhelming satisfaction.