Takumi, a stepfather, secretly harbors feelings for his stepdaughter, Sumire, as a woman. Until now, he has played the role of a good father as the remarried husband of Sumire’s mother, Yumiko. However, faced with Sumire’s youthful and voluptuous body, he can no longer contain himself. Driven by an unbearable longing and intense lust for Sumire, Takumi devises a plan. It is a despicable scheme—to attack Sumire in the bathroom while Yumiko is away. In the bathroom, Sumire would be naked… unable to escape. Seeing this as an opportunity, Takumi carefully executes his cunning plan, forcefully barging into the bathroom and ultimately assaulting Sumire… Just as he achieves his dark desire, something unexpected happens—his wife, Yumiko, suddenly returns home. In a desperate situation, Takumi narrowly avoids being caught, thanks to Sumire. Consumed by guilt and regret, he sneaks into Sumire’s room in the middle of the night. As he falls to his knees and begs for forgiveness, Sumire responds with unexpected words… Takumi is shocked. However, a few days later, he hears an even more astonishing confession—something he could never have imagined in his wildest dreams...