Index Librorum Prohibitorum/Chronology (Souyaku Toaru Majutsu no Index)

After not being involved in Kamijou Touma's battles for much of December, Index ended up being caught up along with him in the conflict resulting from the colliding plans of Aleister Crowley and Lola Stuart, which resulted in her acquiring her 103,001st grimoire and being freed from the control mechanism which the Archbishop had installed in her. Accompanying Touma and Aleister's group in their effort to defeat the Great Demon, Index returned to her home country, the United Kingdom, amidst the chaos of an invasion, which culminated in a decisive battle which saw the two long-time masterminds leave the stage.

With the one responsible for her initial situation gone and being saved in a similar manner to the first time after an unexpected occurrence, Index has chosen to return home with Touma to Academy City.

Christmas Eve Arc
On the morning of December 24th, after Kamijou Touma's remote remedial lessons were scuppered by a technical failure and not knowing Tsukuyomi Komoe's location, Index accompanied Touma to spend their Christmas Eve in the city, being joined by Misaka Mikoto, who ran into them while fleeing from a group of Tokiwadai teachers and students. After wondering how to spend the time, they ended up having a game of darts in a bar, with penalties.

Following the game's conclusion, the group encountered Misaka 10032 and Last Order, shortly before getting caught up in an attempt to kidnap the latter by individuals seeking to thwart Accelerator's Operation Handcuffs, a plan to eliminate the Dark Side of Academy City. After Touma defeated Maidono Hoshimi and the kidnapping was thwarted, the group learnt of Accelerator's endeavour and decided to face the mastermind behind the resistance, Director Neoka Norito.

Arriving in the evening as Anti-Skill was about to move in, the group witnessed an explosion at Neoka's home, set off by Neoka himself as part of a ploy to fabricate injuries and blame Anti-Skill to impede their investigation and buy time to destroy evidence. With Mikoto's ability, they scaled the building and got to the roof before Neoka could have himself injured and escape via air ambulance, forcing the director to try to eliminate them himself. While Neoka initially held the upper hand due to unexpected use of magic acquired from R&C Occultics, Touma and Index soon recognized what he was doing, and with Othinus's help, Touma was able to turn the tables and managed to defeat Neoka in a final physical clash before collapsing himself due to his accumulated injuries.

After the group left the scene and returned to street level, Touma was suddenly approached by Anna Sprengel, the one behind R&C Occultics, who swiftly moved in before the others' eyes and kissed him, exposing him to the contents of a black pill in her mouth.

Christmas Day Arc
On Christmas Day, Index visited the hospital to see Touma, and prayed in the hospital's chapel, knowing the severity of his condition, caused by Anna Sprengel infecting him with St. Germain.

While Touma was facing Anna, Index and Othinus worked to save the many injured espers brought into the hospital who were in danger from the magic they had learnt from R&C Occultics and used without knowing the deadly side-effects, with a simple Christmas charm being ironically prominent among them.