Since A Certain Magical Index is very long and its details vary in its various media, this recap will group by story arcs, taking note of the differences between the light novel, anime, and manga adaptations. See here for A Certain Scientific Railgun's recap page. Warning! Recap pages do not get spoiler tags. All spoilers on these pages will be unmarked.
Side StoriesThe chronological order of these side stories in relation with the original series and with each other is not clear.