Toaru Majutsu no Index: New Testament-Volume 2, Prologue: Unknown Purpose, but Still a Threat. Radiosonde_Castle.

London, England.

A great number of people gathered within St. George’s Cathedral.

It would not have been wrong to call them priests and nuns.

But given their current role, they would more accurately be referred to as magicians. The men and women both young and old who had been called there were exchanging all sorts of information and communicating with allies in distant lands. They were doing these things with such vigor that it destroyed the normal stillness of the cathedral.

“What is the situation?” asked an Asian magician named Kanzaki Kaori.

Her black hair was pulled back in a ponytail, her T-shirt was tied off at the bottom revealing her navel, and her denim jacket and pants had the fabric cut off, revealing one arm and one leg. She had a long Japanese sword hanging down from a Western belt, so she did not look much like someone related to the Christian Church, but even so, she was the Priestess who stood at the top of a denomination that had been passed down within Japan.

“It has risen even further than before,” responded Sister Agnese.

The small girl’s hair was made into braids about as thick as pencils, and she was originally from the Roman Catholic Church.

“Its altitude is now 52,000 meters. It has passed over the UK and is now heading over Eurasia... France, to be exact.”

Agnese lightly waved her fingertips in midair, and a video was displayed on the cold wall of the cathedral.

It showed an area of the sky that had no clouds and almost no oxygen.

A cross-shaped construction could be seen floating in that clear blue sky whose lack of impurities actually made it seem more damaging to living things.

There was nothing around it with which to compare its scale, so it was difficult to accurately determine its size, but... 𝒇𝑟e𝙚𝑤𝙚𝐛𝗻𝐨ν𝚎𝘭.c𝐨m

“Both its length and width are about twenty kilometers, right?”

“If something that large fell from that height, there would be no avoiding an ice age.”

“...”

Kanzaki looked at the video, and her gaze sharpened slightly.

Given its shape, its massive scale, and the fact that it was floating in the sky, Kanzaki doubted that she was the only one that was reminded of "that" fortress that had once plunged the world into chaos.

“According to the information the science side has supplied,” said Agnese as she continued her report, “the air is so thin at that altitude that an airplane cannot maintain the power needed to keep itself afloat- lift, I think they called it. And while one could reach that altitude with a rocket, it would be unable to remain at that altitude. It would just continue on up, so it would be difficult to interfere with the fortress. Either way, it will be tough to send people onto it with parachutes.”

“Then how is it floating? Is it using magic...?”

“We don’t know.” The short nun shook her head. “It seems that an Academy City-made balloon called Mesosphere Radiosonde carries an observation equipment that can float at this altitude. ...Look, around here. Can you see the gas tank-like things?”

Agnese zoomed in the image, and two hundred to three hundred of what looked like metal spheres could be seen on the bottom of the cross-shaped fortress.

“For convenience’s sake, we have started calling the target 'Radiosonde Castle'.” She paused for a second. “The most likely candidate for what's giving it lift is this mass of balloons. The science side has a similar opinion, but they say they do not have any idea what kind of gas could give the necessary lift with only that many tanks. Of course, we don’t know if they truly do not know or if they are holding back on information.”

Kanzaki brought her hand up to her chin.

“...So we don’t even know if this enemy is from the science side or the magic side. Although they’ve suddenly taken action on a level that could destroy the world...”

“The higher ups have put together a separate unit to investigate where it originated from. It started floating up from Iceland, so it sounds like they will be investigating around there. A lot of different organizations are going to be sent out on this one. ...I think it would be best if you just focused on your own job.”

The job that Kanzaki had been given was of course to resolve the issue of Radiosonde Castle.

They did not know where exactly the enemy intended to drop it, but they could not just sit idly by and let it happen.

“So what exactly am I to do?”

“It seems the science side is thinking of shooting it down with ballistic missiles, but as I said before, we do not know for sure what system is giving it lift. The balloons on the bottom are merely one theory. If something were to provide too much of a shock to the system and send it down all at once... well, it could be like an asteroid falling.”

“In other words, we need to find out how exactly the fortress is floating before we can actually do anything? And we can’t do that by viewing it from a distance, so someone has to actually get aboard Radiosonde Castle?”

“At the very least, the source of its lift has to be analyzed. And whether it’s from the magic side or the science side, we need to know whether anyone is aboard and what weapons or spiritual items it may have,” said Agnese as if she were checking things off a list one by one. “If possible, it would be best to interfere with the source of its lift while on board, thus causing it to slowly lower bit by bit. That way, this whole thing will not end in an ice age.”

“But you said there was no way to get to Radiosonde Castle, right? You said an airplane cannot get enough lift and a rocket would only pass by for an instant.”

She could not recommend using a magical means of flight.

There were plenty of ways one could fly using magic, but the magical means of being shot down were too accurate, so one could be interfered with at any time. It was so major that an extremely famous legend involving Peter, one of the twelve Christian apostles, had been created.

Of course, there was someone behind that situation.

They did not know if they were from the science side or the magic side, but if their opponent was a magician, any magical flight Kanzaki took would be easily crushed. In a situation where failure meant the destruction of humanity, Kanzaki could not use such an unstable method while she held the trump card.

“It seems our leader is currently discussing with the science side a means of interfering with Radiosonde Castle.”

“...So there are multiple options and we just need to stay put for now, hm?”

Kanzaki stared at the image on the wall, and realized that she was not properly controlling her emotions.

She was dealing with a threat to the world.

Kanzaki wondered if what she was feeling was what “that boy” had always been holding within him up until he disappeared into the Arctic Ocean at the conclusion of World War III.

As a professional magician, she had taken risky actions dealing with dangers suitable for someone of that position plenty of times, but she had not dealt with situations on such a great scale enough times to even start a count.

And in all the previous incidents she had dealt with, she had wielded her power within the relatively stable confines of the magic side. This time, however, she did not even know whether her opponent was with the science side or the magic side, so her past experience could end up being of little help.

But that boy had walked through that kind of world.

He had gone between the two worlds of science and magic and had faced many opponents and stopped many tragedies without knowing whether his own position was a stable one.

“(It is imprudent of me as a professional magician to think this...)”

His existence was a large one.

Even she, one of the fewer than twenty Saints in the world, felt that.

“(...But if only that boy were here, he would not even have to be heading to the battlefield. If only that boy were here, that alone would change the flow. Why does it seem that way to me...?)”

That boy had sunk into the Arctic Ocean and was gone. f𝑟e𝒆𝘄𝐞𝚋𝚗oѵ𝐞𝗹.c૦𝑚

She could no longer rely on him, so she had no choice but to continue fighting in a world where he was not.

Kanzaki did not think that she was the only one that felt that way. Even though it did not show on their faces, Itsuwa, Tatemiya Saiji, and the others of the Amakusa Church had made up their minds.

As Kanzaki got a bit mad at herself for only being able to think of him in the past tense, Itsuwa, a girl from the same Japanese denomination as her, spoke to her with one hand covering up the microphone on her cell phone.

Itsuwa had to be feeling just as down about it as Kanzaki- if not more so.

“...Umm, I just received word that Kamijou-san has returned to Academy City.”

“Ehh!? How!?”