A Certain Magical Index

is a Japanese light novel series written by Kazuma Kamachi and illustrated by Kiyotaka Haimura; the series is published by ASCII Media Works under their Dengeki Bunko imprint. The series was made into an anime and aired between October 2008 and March 2009, containing twenty-four episodes. An anime adaptation of the side story manga series will be produced. Funimation Entertainment has licensed the first anime seasons of Index and Railgun.

Plot
Toaru Majutsu no Index is set in a city of scientifically advanced superhuman students, but in a world where magic is also real. Tōma Kamijo's right hand, the Imagine Breaker, will negate all magic, psychic, or divine powers, as well as his own luck. One day he finds a young girl hanging on his balcony railing named Index. She turns out to be a nun from the Church of England, and her mind has been implanted with the —all the magical texts the Church has removed from circulation. His encounter with her leads him to meet others from the secret world of science and magic and an adventure with his friends where science and magic collide. Tōma's unusual power places him at the center of conflicts relating magicians and science-based in Academy City. As Tōma tries to help and protect his friends, he learns the people he knows are not as they appear and begins to attract the attention of magicians and espers alike as they try to unravel the secrets of Academy City and Index.

Characters

 * Touma Kamijou - A "powerless" esper who resides in Academy City. He possesses the ability to nullify esper abilities and the supernatural on his right hand, but it also seems to affect his luck as well.
 * Index Prohibitorum Librorum - Also known as Index, a nun-in-training under the care of the Anglican Church. She holds the knowledge of 103,000 magical books, and was on the run from pursuers from the Anglican Church. In her attempt to escape their pursuit, she meets Touma in a chance meeting.
 * Stiyl Magnus - A red-haired priest from the Anglican Church, and one of two pursuers of Index. He is an expert in fire magic with the use of runes.
 * Kaori Kanzaki - A powerful Japanese magician whose abilities are focused on strengthening one's body instead of the conjuration of magic spells, and Stiyl's companion in the search for Index. She is one of twenty powerful magical figures called Saints.

Official

 * Anime Series Official Site (Japanese)

Other Sources

 * Wikipedia Article on Toaru Majutsu no Index