Five years have passed since losing his mother, and Naoki has been living with his father in a single-parent household. Juggling school and household chores, he's managed to get by with just the two of them. One day, returning home, Naoki is greeted by an elaborate home-cooked meal—and the sight of a young woman in their kitchen. The woman is Mika, his father's former secretary. She suddenly announces she's about to become Naoki's stepmother. "Your father and I have decided to get married," she says. Young, beautiful, and tied to his father's past, Mika's presence awakens feelings in Naoki he can't suppress. As her role in the household grows, so too does his forbidden attraction, blurring the lines between family and desire.