District 23 of Academy City was an industrial zone that specialized in aviation and space. All of Academy City's major airports were centered in District 23.
The district was covered in runways and rocket launch sites, so it lacked tall buildings like the rest of the city. As far as the eye could see, it was flat asphalt with occasional control towers and laboratories sticking out.
"It's like a field made of stone and iron…"
Kamijou said this as he stepped off the train and looked out at the landscape stretching out in front of him.
This was the place where he had fought Oriana Thomson during the Daihaseisai, but he got the impression that the security was even tighter now.
He put the grocery bags he had been carrying in a coin locker at the station. Since there were a lot of researchers in this city, the coin lockers were airtight and one had the option of making them refrigerated.
But…
"…This is expensive. Do these things usually cost this much per hour!?"
"Nyah. Looks like it'd be cheaper to just throw those bags out and buy the stuff again at a cheap super market when we get back."
Tsuchimikado had a point, but Kamijou didn't like wasting food. He put the bags in the locker, recorded his fingerprint, locked it, and activated the refrigeration option.
Kamijou headed for the station's exit and spoke to Tsuchimikado.
"I assume we're catching a plane since we're in District 23?"
"Well, we're leaving the country."
"Seriously!? …Wait, did someone get my passport?"
"Nope."
Kamijou fell silent at Tsuchimikado's one word response.
Tsuchimikado sounded bored as he continued speaking.
"It's not like we're going for a trip overseas. Our activities are completely unofficial. And if we're found out, we'll be in international trouble that pales in comparison to not having a stamp or two in our passports."
"I-I see."
There were plenty of things he wanted to say, but the matter-of-fact way Tsuchimikado said that made him wonder if this way really was better.
After exiting the station, they were at a large-scale bus terminal. In District 23, one traveled by taking busses instead of walking.
Tsuchimikado found the bus heading to the international airport and got on; Kamijou followed suit.
Since the district had many runways and lacked buildings, the road was straight as an arrow. The speed limit was fairly high as well; the posted signs noted 100 kph.
With the asphalt plain out the window, even the gray horizon was man-made.
Large white clouds of steam could be seen rising up from the horizon.
A low-pitched tremor shook the glass, causing vibrations.
"Oh, a rocket. Looks like it launched fine."
Tsuchimikado sighed as he said that.
Kamijou pulled out his phone and activated the television function. The news was showing various angles of a rocket leaving the ground.
"They're saying it's Academy City's fourth satellite. I wonder if that's true or not."
"If they're launching a rocket now, one of the reasons will be to get people speculating about it. People will say it's everything from a military satellite to a test launch of an ICBM. The more possibilities, the more effective it is in holding others in check."
(So this is what information warfare is…)
Kamijou suddenly froze.
"…Wait. What about Index?"
He didn't want to take her anywhere dangerous, but he couldn't exactly leave her alone with no food.
"Don't worry. Maika will be going to your room, Kami-yan. She'll probably be only a third as hungry as usual after Maika's done with her."
Kamijou was relieved to hear that, but then realized that his sole purpose in Index's eyes was to make food for her.
Before long, the bus arrived at the international airport.
Kamijou got off the bus and checked the time on his phone.
"Tsuchimikado. Where exactly are we going anyway?"
"France."
Tsuchimikado responded casually.
"Ugeh!? Europe! That's a long ways away… Wait, how long are we going to be gone? And doesn't a flight to Europe take something like 10 hours?"
"No, we'll be there in just under an hour."
"Hah?"
Kamijou responded in confusion.
Tsuchimikado seemed to be annoyed at having to explain, so he simply pointed to the runway a bit away from the terminal building.
There were multiple large passenger planes lined up, each a few dozen meters long.
"We'll be getting on one of those."
"…Please tell me you're kidding."
Kamijou was almost speechless as he asked Tsuchimikado for confirmation.
He had ridden on a plane like that once before.
"If I recall correctly, that's the type of plane that took me from Venice to Japan."
"Yeah, that's what I heard, Kami-yan. I didn't have much involvement in the whole 'Queen of the Adriatic' incident, so I don't know the details."
"So are those really the ones that fly at 7000 KPH?"
"Hahaha," laughed Tsuchimikado. "The faster the better, right?"
"That's too fast!! When I was riding that thing, it felt like a thick metal sheet was slowly crushing my body! Index had finally started opening her heart to the science side and that thing made the shutters over her heart seal up tight!!"
There was also the part where Index had ordered some in-flight food and it flew behind her spectacularly.
"Oh, c'mon, Kami-yan. We're heading out on an unofficial overseas mission. Did you really think we were going to head to France while we leisurely ate an in-flight meal and watched a movie?"
"W-well, no. I was expecting there to be a little more tension than that, but… Wait. We're really getting on that thing? I-I really can't recommend the experience!!"
"Don't worry. Don't worry. After you exceed Mach 3, an amateur won't feel the difference."
"How the hell is that supposed to make me worry less!?"
Kamijou kept complaining, but Tsuchimikado stopped listening and started explaining what to do once they got on the plane. It seemed there were no other planes, so they really had no choice. Tsuchimikado led Kamijou through a door for "authorized personnel only" and down a corridor that led them to the supersonic passenger plane while circumventing the general-use gate.