The series Junjou Romantica series actually contain 3 main stories within them, which are loosely interconnected, with different couples as the main characters. 
Junjou Romantica 
Misaki, struggling to pass his college entrance exams, is in need of a tutor to help pump up his failing grades. Unfortunately, his only option is the cool and sexy Akihiko Usami. Usami happens to be a famous boys&rsquo; love novelist, which doesn&rsquo;t exactly float Misaki&rsquo;s boat, especially since his main characters are &ldquo;Akihiko&rdquo; and &ldquo;Takahiro,&rdquo; the name of Misaki&rsquo;s older brother and Usami&rsquo;s childhood friend. Understandably, Misaki is pretty disgusted by the thought of someone using his older brother as his personal fantasy-material, but then after some tender loving from Usami, Misaki is also pretty confused. He may even be developing feelings for the older man...And when Takahiro introduces them to his lovely (female) fianc&eacute;e, so begins the bumpy relationship of this odd couple, filled with comedy and pure romance. 
Junjou Egoist 
Kamijou Hiroki is a broken man, consumed by unrequited love for his childhood friend, Usami Akihiko (the writer character in Junjou Romantica). Along comes Kusama Nowaki, whose name "Nowaki" means "typhoon", an orphan working his way through life since middle school. Like the typhoon he is named for, he whirls into Hiroki's life and heart, blowing all resistance away before him. 
Junjou Terrorist 
As fate would have it, Professor Miyagi Yoh (whom Hiroki is working with as assistant professor), and Takatsuki Shinobu, a high school student, cross paths. Miyagi, when in high school, loved (and still cannot forget) a female teacher who had a terminal illness, is now faced with Shinobu, who just says whatever is on his mind. The wheel of destiny is beginning to turn once again... 
Note: Includes a short story called Junjou Minimum

Three very different couples caught up in a storm of pure romance! 
Romantica: Misaki is struggling to prepare for his college entrance exams, so his brother arranges for a private tutor. But Misaki's nightmare is just beginning when his tutor, Usami, comes on to him! How will Misaki ever manage to pass his exam? And why does he feel so mysteriously drawn to Usami? 
Egoist: Just when Kamijou's life is at its lowest, he has a chance meeting with a man who never lets anything hold him back: Nowaki. His name means "typhoon," and he's about to take Kamijou on a whirlwind ride that will turn everything upside-down. 
Terrorist: Miyagi always seems to shrug off the cares of the world with a joke and a smile, but even he has problems, although he doesn't let them show. Foremost is Shinobu, a relentless young man who's adamant that they're destined to be together. 
(Source: RightStuf)

The second part of Junjou Romantica continuing the story.

The third season of Junjou Romantica. 

It follows the ongoing story of three couples:
 
The Romantica relationship between college student Misaki Takahashi and his tutor, Akihiko Usami.
 
The stormy Egoist couple—Professor Hiroki Kamijou, a tsundere, doted on by Nowaki Kusama.
 
The dramatic Terrorist couple—divorced literature professor Yo Miyagi, and his younger lover, Shinobu Tatasuki.
 
It’s complicated.
 
But so worth it.
 
(Source: Crunchyroll, edited)

Tags