Angel Fall Arc

Angel Fall Arc is a story arc that occurs in the Toaru Majutsu no Index storyline. It concerns with the activation of a world-wide spell known as Angel Fall, a spell that switches the elements, as well as the appearances of persons around the world. The most notable affect of Angel Fall is the expulsion of an angel to earth. The arc focuses on Touma, Kaori and Motoharu trying to find the culprit and stop Angel Fall, while Touma deals with his family that he meets for the first time since losing his memories, during an involuntary vacation outside of Academy City.

Aftermath of the Sisters Arc

 * Main article: Sisters Arc

After defeating Accelerator, delinquents looking for prestige and glory increased their hostilities on Touma as he was the one to have defeated Academy City's strongest esper. Because of this, Touma is forced to leave Academy City (along with Index)at the urging of Tsukuyomi Komoe, while Academy City quell the situation during his absence.

Activation of Angel Fall
Kamijou Touya – Touma's father and collector of souvenirs from all around the world – unitentionally activates Angel Fall after arranging the various souvenirs in his home in accordance to the principles of feng-shui in an effort to stop his son's vast misfortune, and after accidentally leaving his house unlocked to go to Touma's current location.

Trivia

 * This arc is notable for being highly edited for the anime adaptation, notably the removal of Hino Jinsaku.