Hard work and dedication have finally paid off for Chiaki Muraoka, and she is now attending the school of her dreams: Otomegawa Academy Private High School. As she enters the dorm on her first day, she is forced to take part in a lottery, which she wins. Her prize is the privilege of rooming with Katsuho Saekihara, the academy director's grandson. He is cheerful, princely, and gorgeous, and Chiaki can't help but be dazzled by him—but as it turns out, this boy's true self is quite different. Katsuho is actually a perverted sadist, something that Chiaki quickly discovers when his demeanor changes and he begins kissing her passionately.

Having drawn the ire of every girl at school for rooming with Katsuho, he proposes that they become a couple despite Chiaki's objections. Soon, however, Chiaki begins to realize that there is more to Katsuho than she first thought—and that her feelings of disdain toward him are slowly turning into something else.