In front of a camera, roommates Mao Tsuchiya and Hisashi Ootomo make three promises: Mao must not tell anyone Hisashi is gay and in a relationship with another man; Hisashi must never fall in love or make any advances on Mao; and one must not disturb the other's "personal time." Thus begins their second year of cohabitation.

However, everything starts to crumble when the film club—of which Mao is a member—wants to cast Hisashi in the lead role for their upcoming movie. The problem arises with the movie's plot, as it is about boys' love—a romance between a delinquent and the class president. Mao is adamant to dissuade Hisashi from becoming the protagonist due to their first promise; but, to his surprise, Hisashi is easily convinced by the director.

After imagining Hisashi as the delinquent he is playing, Mao becomes overly conscious of his presence. He knows Hisashi is just a friend and out of his reach, but Mao cannot keep lying to himself anymore—his feelings toward his roommate may no longer be purely platonic.