On the verge of her entrance exams, Riko continues to secretly meet her boyfriend, Yuta, trying to avoid detection by her mother, Etsuko. Noticing their behavior, Etsuko sternly declares that romance is forbidden until the exams are over, for the sake of her daughter's future. But her words fall on deaf ears. A few days later, Yuta visits Etsuko and pleads with her—he will end his relationship with Riko if she surrenders her body to him. After a moment of hesitation, Etsuko gives in, overwhelmed by her own hidden desires. What began as an act to protect her daughter soon spirals into a whirlpool of forbidden emotions.