Following the events of last episode and the activation of Index's defense mechanism Touma struggles to hide his amnesia from Index.

School’s back in session and that means new transfer students – one of which is Index! In class, Komoe offers more insight into the realities of life as an esper – and a powerful new magical presence is detected in Academy City.

Kamijo, Index and Kazakiri join forces to take on Ellis. When the battle ends, and with the support of Index, Kazakiri returns to the place of her origin. Later, Tsuchimikado ponders Aleister’s role in recent events.

It’s the Daihasei Festival, and everyone’s parents are in town! As Toma and Mikoto compete against each other in various events, a Roman Orthodox magician and her assistant negotiate to purchase a powerful relic from the English Puritan Church.

As Toma and the others come close to beating Oriana, the motivations behind her actions are finally revealed. But taking out Oriana might not be enough to stop her plot from reaching a catastrophic completion!

Accelerator attempts to make amends for his past by doing a few good deeds, but ends up attacked by a group led by someone from his past. Meanwhile, Toma discovers strange goings-ons in the police force and overhears talk of an intruder in Academy City.

When Accelerator deduces who is pulling all the strings in Academy City, no person—or building—is safe from his rage. Meanwhile, Toma goes on a mad dash through the city looking for Last Order, but what he finds is an angel.

Accelerator is injured, but even in that state he’s approached by a city-employed organization that wants to recruit him. As rumors of an impending war spread throughout Academy City, the students in Toma’s class decide to throw a party.

Kanzaki battles Acqua under Academy City, but finds herself overpowered by his might. Mikoto runs into Kamijo after he sneaks out of his hospital room. Kanzaki works with the Amakusa Church members to find a way to beat Acqua.