Misaki Takahashi is a regular high school student who is preparing for his university entrance exams. In order to reduce the stress of studying, or so he hopes, he accepts the help of his older brother's best friend, and famous author, Akihiko Usami. However, Masaki is about to find out that Usami's books are of a very naughty genre, and that there may be something naughty waking up inside Masaki as well. Junjou Romantica also follows the story of two other couples loosely connected to Masaki and Usami's "Romantica." Egoist shows the very passionate, but often complicated, relationship between university professor Hiroki Kamijou (whose life has reached an all time low) and paediatrician Nowaki Kusama, who falls for Hiroki at first sight and would do anything to make him happy. The third story, "Terrorist," shows just how obsessive love can become when rich eighteen-year-old Shinobu Takatsuki finally discovers something that he cannot have so easily—the literature professor You Miyagi. There is passion abound as these three couples try to achieve their goals in life while also falling into temptation and anguish with their partners.

In the wake of a third world war which left Japan in ruins, an organization known as Vischio seized control of Tokyo and renamed it Toshima. Taking place in its back alleys are battle games known as Igura, overseen by the Vischio, in which contestants battle and bathe in each other's blood to earn the chance to go up against its tournament's king, Il-re. Igura is not the only fighting tournament around; Bl@ster is a similar yet vastly different game since it prohibits murder and the use of weapons. The only way to win is by knocking out the opponent. Akira, a young man isolated from his family, is known to be undefeatable at Bl@ster. However, his life on the top is shattered when he is accused of murder. Unable to prove his own innocence, all hope is seemingly lost... that is until a mysterious woman named Emma appears and offers him a chance. Now, to regain his freedom, Akira must participate in Igura and ultimately defeat Il-re. [Written by MAL Rewrite]

The band "given"—comprised of Ritsuka Uenoyama, Mafuyu Satou, Haruki Nakayama, and Akihiko Kaji—has advanced to the final screening of the Countdown-fes Amateur Contest, in which they will be judged on their live act. Although enthusiastic, they worry about having only one original song to perform. Mafuyu embraces the idea of learning more about music in order to create new, emotionally resonant songs. In this regard, he unexpectedly receives help from Ugetsu Murata, Akihiko's on-again, off-again lover. Ugetsu has unsuccessfully tried to let go of Akihiko, who himself is torn between lingering feelings for his past and an uncertain resolve for the future. As the competition draws near, Haruki uncharacteristically begins to doubt his place in the band and the trust he shares with Akihiko. It is a given that not all attachments last forever, but it remains to be seen what can be salvaged from the ruins of heartbreak—or if only regrets will endure. [Written by MAL Rewrite]

Misaki Takahashi is a regular high school student who is preparing for his university entrance exams. In order to reduce the stress of studying, or so he hopes, he accepts the help of his older brother's best friend, and famous author, Akihiko Usami. However, Masaki is about to find out that Usami's books are of a very naughty genre, and that there may be something naughty waking up inside Masaki as well. Junjou Romantica also follows the story of two other couples loosely connected to Masaki and Usami's "Romantica." Egoist shows the very passionate, but often complicated, relationship between university professor Hiroki Kamijou (whose life has reached an all time low) and paediatrician Nowaki Kusama, who falls for Hiroki at first sight and would do anything to make him happy. The third story, "Terrorist," shows just how obsessive love can become when rich eighteen-year-old Shinobu Takatsuki finally discovers something that he cannot have so easily—the literature professor You Miyagi. There is passion abound as these three couples try to achieve their goals in life while also falling into temptation and anguish with their partners.