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.

With the seniors having graduated from high school, the determined swimmers eagerly take on their futures with a dream to fulfill. Now attending Hidaka University in Tokyo, Haruka Nanase unexpectedly runs into Shiina Asahi, an old teammate and friend from his middle school days. Consequently, the troubling memories regarding his middle school swim team resurface, as it was a time when Haruka's views on swimming became negative and led him to quit the team. Haruka later reconnects with his other middle school classmates; all except for Ikuya Kirishima, who still resents Haruka for quitting the team, resulting in its disbandment. Aware of the issues between them, Haruka resolves to improve his friendship with Ikuya. However, he quickly realizes that making amends with an old friend isn't his only obstacle. Facing the reality and challenges of encountering higher calibre swimmers, Haruka must work hard to establish himself if he dreams of competing on an international level. [Written by MAL Rewrite]

In the distant future, a majority of humans have left the Earth, and the Galactic Alliance of Humanity is founded to guide exploration and ensure the prosperity of mankind. However, a significant threat arises in the form of strange creatures called Hideauze, resulting in an interstellar war to prevent humanity's extinction. Armed with Chamber, an autonomous robot, 16-year-old lieutenant Ledo of the Galactic Alliance joins the battle against the monsters. In an unfortunate turn of events, Ledo loses control during the battle and is cast out to the far reaches of space, crash-landing on a waterlogged Earth. On the blue planet, Gargantia—a large fleet of scavenger ships—comes across Chamber and retrieves it from the ocean, thinking they have salvaged something of value. Mistaking their actions for hostility, Ledo sneaks aboard and takes a young messenger girl named Amy hostage, only to realize that the residents of Gargantia are not as dangerous as he had believed. Faced with uncertainty, and unable to communicate with his comrades in space, Ledo attempts to get his bearings and acclimate to a new lifestyle. But his peaceful days are about to be short-lived, as there is more to this ocean-covered planet than meets the eye.

In a dark corner of the universe, intergalactic criminal Kain breaks out of prison and destroys the Galaxy Police Headquarters. Basking in the afterglow of the terror and destruction he has caused, Kain sets his sights toward a much bigger prize waiting on Earth. Meanwhile, Tenchi Masaki and his crew are watching some old home videos of his mother, Achika. As the film rolls, Achika slowly starts to vanish. While watching her fade away, Tenchi also begins to disappear. However, thanks to a device created by Washuu Hakubi, Tenchi is not gone for good. The gang soon learns about Kain and deduce that he must have done something to Achika, which has resulted in time being altered. To save himself and maintain the future, Tenchi travels with the girls back in time to protect his mother from her fate.