Toaru Majutsu no Index Wiki:Overview

Toaru Majutsu no Index is a light novel series which tells the story of a boy with an unusual gift--and curse-- and his encounters with the worlds of science and magic. Soon, he finds himself in the middle of the conflict of these worlds, primarily the Magic Cabal in one side, and Academy City on the other. The series explains the workings inside these worlds and the people who will end up working with him in his quest to save others.

Meanwhile, Toaru Kagaku no Railgun acts as a supplement to the story of the light novels, adding more information into the existing facts within Academy City. The story focuses on third-rank Level 5 Misaka Mikoto and her own misadventures in Academy City. With Judgment member and roommate Shirai Kuroko and new friends Saten Ruiko and Uiharu Kazari, they dwell on seemingly normal lives as Misaka finds out more on the hidden side of Academy City, which is far from the utopia it's supposed to be.

Settings
The series is set in an alternate present, where part of Japan's capital Tokyo becomes a semi-independent territory called Academy City. In this city, normal students undergo a special academic program designed for them to develop esper abilities. A certain classification scheme sorts out the students according to the level of their abilities, with Power Users (a term used for students under the Power Development Curriculum) from Level 0 to 5.

At the same time, the Magic Cabal, a collective term for magicians, initiate their infiltration of the city. In this world, magicians (ruled by religious organizations like the Roman Catholic Church and the Anglican Church) are enemies with the inhabitants of Academy City, who is supervised by none other than Aleister Crowley, himself a former magician.

Toaru Majutsu no Index
Kamijou Touma, a high school student, has an encounter with a girl in nun's clothing. The girl later reveals that she's Index Prohibitorum Librorum, a girl with 103,000 grimoires in her head and a fugitive from two magicians who pursue her.

It is revealed that those two magicians are actually her guardians, who would require her presence to perform a memory-cleansing spell which has been performed to her before to keep the secret of the treasured books inside her head intact. They realized, though, that the ritual was merely a method to keep her from gaining any friends. Touma decides to intervene and he manages to save Index from the ceremony, at a price--his memories.

He lives the next few days trying to sort out his life; without his memories, he tries to fake his experience with his friends and loved ones, which he managed to pull off. Soon, he finds himself trying to save Index again, this time, from its previous guardian, an alchemist named Aureolus Izzard, who has the ability to translate his thoughts to reality.