Attack on the Queen Britannia

The Attack on the Queen Britannia was a battle which occurred one December morning in the current year of the story timeline, shortly after the Crowley's Hazard invasion of the United Kingdom.

Taking place in the Irish Sea, near to the, it was an assault carried about by British forces and several groups from Academy City on the hijacked Queen Britannia, in order to prevent Coronzon from using the stolen Honours of Scotland to seize control of the United Kingdom's magical system and performing the Ceremony of Mo Athair which would have resulted in the destruction of the world.

Accelerator VS Nephthys
After a few hits from the ice tornado against the ship, seeing that it wouldn't accomplish much, Accelerator had Qliphah Puzzle 545 complete her manifestation and broke into the ship. He decided to head for the engine room to break the propeller shaft and immobilize the ship, but before he made a move, he encountered Hamazura Shiage, bleeding heavily due to refining magic power as an esper in order to revive Dion Fortune. As Accelerator prepared to swat him aside and continue on, he was kicked by Nephthys in a surprise attack through a wall and then tackled through another wall into the ship's opera house.

In the subsequent battle, Accelerator thwarted Nephthys's initial attempt to use her tears on Qliphah Puzzle 545 again by breaking a sprinkler. Nephthys was unaffected by his next attack and subsequently made use of the water herself, dropping it down as a blade. Finding his reflection wavering from the water partially interfering with the electromagnetic waves and being struck by a piece of debris, Accelerator was forced to disperse the water but in the process created an opportunity for Nephthys to use her tears again. As Qliphah Puzzle 545 tried to contain her power as it was sent out of control, she was contacted by the Will of the Misaka Network through her connection with Accelerator and received assistance in turning things to his advantage, realizing her essence as a guide to the Abyss. Through this, Accelerator became capable of dealing lasting wounds against Nephthys.

The clash ultimately ended with Accelerator bloody from the side-effects of relying on something like magic as an esper and Nephthys tangled in the bars in the ceiling for the stage lights.

Aftermath
After being split in half, the Queen Britannia was left slanted and sank in the half hour following noon. The various groups from Academy City took advantage of the situation created by the sinking in order to slip away, though Mina Mathers recovered the Scottish royal treasures and returned them to Queen Elizard before leaving. Kamijou Touma escaped immediately after the ship was blown open and fled across the ice, in order to prevent the dangerous and now-unsealed entity from killing anyone.