Kamijou Touma is a student living in Academy City, a highly advanced place in terms of technology. Despite being gauged as a level zero esper (no powers), he possesses on his right hand the Imagine Breaker, an ability that negates any power whatsoever. Touma finds a young girl named Index who is trying to run away from Necessarius, a powerful magic organization that she is member of. Blessed with the skill of memorizing any sort of information, she holds 103,000 forbidden magical books within her head. As science and magic cross paths, Touma must face several dangers amid espers and magicians who appear at the exciting scientific town.
Index is still a fugitive and many powerful magical organizations and individuals want to take her to use the books in her memory, eliminating her in the process. War between those organizations is also starting to emerge. Index can only rely on her friend Tōma, who has always protected her, along with Misaka and other friends from the Academy.
Academy City is a highly developed place in terms of technology. It is said to be 20 to 30 years ahead of the rest of the world. Eighty percent of its 2.3 million residents are students. The focus of studies here is directed towards esper powers. Misaka Mikoto, one of the top level espers in town, shares a room with Kuroko Shirai, another high level esper who is a member of Judgement, a law enforcing agency composed of students. Both attend to Tokiwadai, a private school reserved for the high-leveled and the rich. Kuroko's partner at Judgement, Kazari Uiharu, is a low level esper who studies at Sakugawa middle school. Her best friend and classmate there is Ruiko Saten, a level zero (no esper powers). Together, the four encounter several adventures in the exciting scientific town.
Tokyo Butei High School is a special school where armed detectives—"Butei"—are trained to use weapons. Kinji Tōyama is a second year student who has a special ability, but he keeps it a secret to maintain an ordinary, peaceful life. However, when he gets caught in a bombing on the way to school, he encounters Aria H. Kanzaki, the most powerful S-Rank Butei student in Assault Studies.
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.
The main fighters are summoned to a tournament that involves the heads of all the schools. But some of the heads send their trust fighters in their place. They don't realize that the tournament is just the face of a conspiracy to take over the clans. Hakufu now has a disciple as crazy and skilled as her and due to her laziness the disciple ends on the tournament in the place of her master. Now they must prove that the destiny imposed by the souls of the fighters living in their own is not always an absolute law.
Senō Natsuru is your normal, everyday high school student. However, he's been chosen to be a Kämpfer, who's objective consists on fighting other Kämpfer with either guns, swords or magic. However, there's catch—first, you can't chose if you're a Kämpfer or not, and second, you must have the body of a girl to use your powers.
Disowned by his father, Jugo Yama has run away from home to the island of Nanae. He begins to live by himself, only to discover his room is haunted by the ghost of Nanana Ryugajo. She was murdered ten years ago, and her killer must be found before she can rest in peace. Before her death, Nanana collected things from all over the world and hid them throughout the island. Using the mysterious powers of these hidden items, they should be able to find the culprit. As Jugo begins his hunt for her collection, however, he discovers he's not the only person searching.
Despite Ryuji Takasu's gentle personality, his eyes make him look like an intimidating delinquent. Class rearrangements on his second high school year put him together with his best friend, Yusaku Kitamura, and his hidden crush, Minori Kushieda. Along with these two comes Kushieda's best friend, Taiga Aisaka. Her delicate appearance contrasts with her brutal personality. Secretly in love with Kitamura, Taiga agrees to help Ryuji with his love interest as long as he helps her get closer to hers.