High school student Misaki Takahashi comes home to find his older brother being fondled by a stranger. Confused by the scene, Misaki learns that the man is actually Akihiko Usami, a well-known novelist and his brother's best friend. As the two gradually get to know each other, Akihiko becomes Misaki's private tutor. However, after discovering the author's latest boys-love novel, Misaki begins to doubt whether he can trust Akihiko regarding his friendship with the student's brother. Meanwhile, Hiroki Kamijou, a university professor of classical literature and Akihiko's friend, is mourning a failed romance. On the verge of a mental breakdown, he meets student Nowaki Kusama, who seeks his help for an upcoming exam. Although Hiroki repeatedly refuses Nowaki's requests, he eventually agrees to assist him. As the two grow closer, further details about the student are revealed. Additionally, when wealthy teenager Shinobu Takatsuki discovers that his older sister has divorced Hiroki's coworker You Miyagi, he immediately wants to date the same man, since You saved Shinobu from a robbery three years earlier. Even so, You does not share these feelings and tries to scare him away. However, the educator soon realizes that Shinobu will do anything for their destined romance. Junjou Romantica collects three love stories, narrating every couple's romance.