To Aru Majutsu no Kinsho MokurokuToaru Majutsu no Index; とある魔術の禁書目録〈インデックス〉; とある魔術の禁書目録; Toaru Majutsu no Kinsho Mokuroku; A Certain Magical Index; 魔法的禁書目錄; 魔法禁書目錄; فهرس السحر; فهرس كتب السحر المحرمة; Некий Магический Индекс; Cấm ma thuật thư Index

The story is set in a world where supernatural powers exist through science, and magic exists through religion. In the story, Touma Kamijou is an ordinary high school boy with terrible academic scores and a power called Imagine Breaker. Imagine Breaker can defeat any other power, but it also undermines Kamijou's own good luck. His Imagine Breaker's immense strength is literally immeasurable, so hapless Kamijou is listed at the supernatural level of 0. He happens to meet a girl in white hanging off his window balcony. The girl says she is being chased by sorcerers, and Kamijou learns that the girl is a Church of England nun whose memories have been forcibly replaced by Index-Librorum-Prohibitorum — the 103,000 forbidden texts of the Church.