Starts out with Aqua fighting against the royal knights. He takes them down easily and manages to get Vileinne to safety using magical horse. It seems Vileinne has crush on Aqua, and cries as he sends her away with his horse. Aqua than fights against Knight Leader one on one. They seem evenly matched at first, but Aqua haven't fully healed from the battle at Academy City while Knight Leader has Carissa's blessing. Knight Leader tries to convince Aqua to leave Britain, but Aqua's answer was "talk is cheap." They crash again and again. As Aqua starts to gains upper hand and is about to strike him down, Knight Leader uses his spell which can turn any damage from any kind of weapon in his sight to zero. Aqua uses last hidden blade hidden within Ascalon, which Knight Leader didn't recognize as a weapon, to take him down.
Touma manages to smuggle in train that's headed to Forkstone. There he meets Floris, Who is a member of the New Light. She was captured by Necessarius at first, but the knights took her back to silence her. Floris asks Touma to help her get out of here. She asks for a key to get her out of her restraints, but Touma uses his Imagine Breaker to break it instead, and alarm goes off. In state of panic, the two jumps off from the train.
Anise and two other nuns managed to escape from the knights, but not the rest of her team. They get on board of a train where they're holding nuns captive in order to rescue them.
Touma managed to get to Forkstone with help from Amakusas sent to search for him. Floris was handed to them (without the knowledge that she was one of the New Light) as well as Vileinne, whom he came across after jumping off the train. At Forkstone he encounters Aqua fighting against the knights as well as Index laying unconscious inside the carriage, and Carissa. Carissa uses Catena's power to create huge shock wave and sends them flying before they get a chance to fight
Aqua managed to save both Touma and Index. Aqua tells him that Fianmma is after Imagine breaker, and now he is going after Fianmma instead. They come to short truce. Aqua leaves to do his own thing, and Touma regroups with Kanzaki and Amakusas. They come up with a plan to attack Carissa, who is at Buckingham Palace right now. The Buckingham Palace works like a lightning rod. In case Catena goes out of control she'll be able to let the power escape via royal subway. There's special Cart that works as hub for the system, and the plan is to use that to attack her instead. They'll feed energy from Caven Compass, a flying fortress Necessarius has.
Touma, Index and Vileinne are the only ones that can go in since they got heavy security against magic in London and only royalty can access royal subway. With Misaka's help they manage to sneak in underground which was closed off to the public. There the three takes down huge paper mache security guard and encounters servants and maids working at the palace. As soon as Vileinne opens up royal subway Itsuwa calls Touma, telling him that they managed to access the hub cart and to get out before they get caught in explosion.
The explosion was not enough to kill Carissa, but enough to put her to 50% output. After the explosion London was filled with magic flammable energy from Catena, so Touma and co. have a feast while waiting for rest of the Necessarius to gather and the gas to die down.
Last battle against Carissa. They enter London with air support from flying fortresses. Catena can slice dimension and create aftermass as a result. Carissa uses that to attack Touma and rest of Necessarius (+princess Vileinne). Touma and Vileinne gets to Carissa first, and start fighting. After Touma gets good beating from Carissa and Griffin Sky (80 meters wide hang glider that can turn its own shadow into huge stake to attack), Kanzaki shows up to save him and others start to show soon after. They start taking down Griffin Sky, but Carissa orders the military ship by the coast to fire bunker cluster missile at the palace (wtf!)
1st princess Lemeria finds out Carissa's other reason for the coup. She wanted to do away with Catena as well as protect England, so she decided to kill rest of royalty and destroy everything that's related to Catena. By leaving her name and Catena in history as a symbol of tyrant, the people won't allow the royalty to create another sword like it and do away with the royalty for good, or so that was her reasoning. Lemeria asks the knights to help her if they feel slightest amount of pity towards her.
Touma manage to stand up and tries to fight Carissa. Carissa orders second bunker cluster to finish them off, but before it could strike Knight Leader shows and stops the missile. Aqua shows as well after destroying radio towers around the area. Kanzaki joins after patching herself up. All four of them go DBZ for while but eventually Carissa gains upper hand by attacking regular mages and knights around to stall saints and Knight Leader.
Queen finally shows up. She says that what Carissa came up with is pathetic, arrogant and nothing more than a show of cowardice. Carissa was ready for show down between two Catena, but the queen throws her's away and tells her that "if you want a change, you have to do something original as this." She takes out English flag as well as welsh flag and calls out the entire country to join the party. She spread Catena's power to entire population of England. "This country isn't as cheap as you think it is", she says.
Everyone around London starts to show around the palace and starts fighting against Carissa. If Carissa loses her focus, original Catena's power will be sucked dry by the people, so she has to take on flying bartenders and fireball throwing maids while trying to keep it under control. During the confusion, Aqua throws Touma to Carissa via Ascalon and he destroys Catena as well as Carissa's face. Carissa is shot across the palace.
Just as everything was about to end well, Fianmma shows up. Carissa is laying on a road all by herself and Fianmma starts talking to her if he should kill her or not. Touma comes in before Fianmma could strike and saves her. Fianmma shows the remote he got and despite Carissa's warning he activates the remote, summoning robot mode Index right in front of Touma, and uses her to attack him. After seeing how remote works, Fianmma leaves.
Sasha in Russia is on the run with her boss, and Vent helps her escape.
Archbishop and the queen claims that having a remote control was only natural. They wouldn't have left Index in Academy City without some sort of safety device. There's only two remotes, one with Archbishop and other with queen. Fianmma took queen's remote. Stiyl is outraged by this. Index will be put under their care for now. Touma asks Stiyl to take care of Index and decides to head to Russia to give Fianmma a good one. End of volume.
credit: Bob4000