Makoto Niwa is a high school boy who, since his parents are away on business, lives with his aunt’s family. It is there he meets his mysterious cousin of the same age Erio Touwa—who happens to tie a futon around her upper body and is a self-proclaimed alien. Her staple food is pizza. Erio had been missing for half a year and was found floating in the sea. She doesn't remember anything about what happened during that period of time, but she began to think that it was the act of an alien and wanders the neighbourhood wrapped in the futon.
Yoshitaka Nakabayashi, a 14-year-old millionaire who got this huge inheritance after his parents died in an accident, found himself needed to be taken care of and tried to hire live-in maids to do the job. Two runaway girls, Izumi Sawatari and her younger sister Mitsuki, stumped into Nakabayashi's mansion and got hired by Yoshitaka immediately, for Yoshitaka is not only a rich boy but also a pervert with uniform fetishes, who wants to be addressed as goshujin-sama (master). Having nowhere else to settle down along with Mitsuki's pet alligator Pochi, Izumi accepted the job reluctantly.
It's the final year of high school for Yui Hirasawa (guitar), Ritsu Tainaka (drums), Mio Akiyama (bass), and Tsumugi Kotobuki (keyboard). The founding members of the Light Music Club. Together with their junior member Azusa Nakano (guitar), they spend their days after school in the music room enjoying tea and sweets, and practicing music. Amidst band practice, preparations for the new student orientation performance, scouting for new members, and student responsibilities they still have time for "After School Tea Time".
Sawako Kuronuma's one wish in life is to make friends. That's a difficult proposition when everyone who meets her cowers in terror, due to her resemblance to Sadako (after whom they nickname her) from the Japanese horror movie series The Ring. Shunned by her classmates, her life starts to change after she befriends her classmate, Shōta Kazehaya, a popular, easygoing and 100% refreshing guy who is nice with everyone, even with her.
Honoka K?saka loves her school. That's why it's bad news for her when she finds out it's being shut down due to lack of new students. In order to bring in more students, Honoka decides to start a "school idol group," which is certain to get the eyes of the public. To make this dream a reality, she gathers together her close friends and classmates to make the best idol unit possible.
High school freshman Yuuta Togashi was once a "Chunibyo patient" i.e. an overly self-conscious middle schooler. He wants to bury this embarrassing past and begins a new life in high school unsuccessfully. His classmate Rikka Takanashi, a "current" chunibyo patient, has found traces of residual symptoms on him and used the fact to force Togashi "making a contract" with her.
Living on the shadow of his prodigious younger sister, Kyousuke Kosaka conducts a normal lifestyle until he accidentally finds out that she hides a secret. In addition to being smart, pretty, and popular; Kirino Kosaka is also an obsessive consumer of anime and eroge (adult computer games). After being assured that Kyousuke is committed to not mock her and keep this concealed from their parents, she starts to share a bit of her world with him. Kirino faces several problems as she tries to keep the appearances and balance her exemplar school life with her hobbies. Her brother then becomes a crucial ally while dealing with all the difficulties that lie ahead.
In a future world where an organization called the GGP has taken control of the world, Rin Ogata was a promising up-and-comming ballet dancer, but suffered a serious injury and decided to quit. Years later in college she comes across a club building and soon finds herself intrigued by a transforming motorcycle like vehicle called a Rideback. She discovers that her unique ballet skills with balance and finesse make her a born natural on a Rideback. However, those same skills also get her into serious trouble with the government.
Haruka Takayama and Yuu Sonoda were inseparable during their junior high school years, but upon entering their senior high school, they end up being seated on opposite sides of the classroom. Having to spend time with more friends, the two decide to do something to make their relationship special.
Yōto Yokodera is a perverted schoolboy who is unable to express his true feelings freely. After hearing about the wish-granting Stony Cat, he decides to try and make an offering to lose his facade, only to meet Tsukiko who wishes instead to be more discreet with her feelings to become more adultlike. Who'd have thought the rumors of the wish-granting Stony Cat turns out to be true; transferring the facade that Yōto wishes to lose into a classmate who needs it more and making it difficult for Tsukiko to show even the slightest of emotions on her face. Being on the same boat, they both search for ways to remedy the situation.
In the "Great Disaster," Japan has been thrown into chaos by onmyouji (a kind of magician). Harutora Tsuchimikado was born into an onmyouji family, but has no power whatsoever. His childhood friend Natsume (another member of the Tsuchimikado family) appears to him one day to take him up the promise he made long ago to become her shikigami (familiar). A battle between onmyouji is about to begin.
Haruka Kasugano and his twin sister Sora have lost both their parents in an accident, and with them all their support. They decide to move out of the city to the rural town where they once spent summers with their late grandfather. At first everything seems familiar and peaceful, but changes come as Haruka starts to remember things from his youth.