Thank You, Willis Carrier
The two mascots looked miserable.
As a stopgap, Mari filled the bathroom basin with cold water and floated a heap of ice cubes she'd pulled from the freezer on top.
"Ahhh, I'm alive."
"Hwaaah…"
Once she carefully lowered them in, it wasn't long before both of them came back to their senses.
She'd known heat wasn't a human monopoly, but she hadn't expected even these two to end up looking like this. Considering the one fan they owned was usually monopolized by her or Siyeon, she could at least understand the suffering.
She let out a long sigh, squatting down to peer into the basin with a pained expression, clinging to the hope of a day that still hadn't come.
"Ugh… You guys and us both. Just hang on until the air conditioner gets here."
They were all suffering together. Feeling an unusual flicker of sympathy, she started to stand and head for the master bedroom—only to spot the bear raising a hand from the water.
"Lady Mari, I was wondering…"
"Hm? What?"
"Couldn't you just have asked someone else to handle this?"
"What, you want me to walk up with three hundred in cash, hand over the address, explain the pipe layout, and ask them to buy it for us?"
Splash shot the bear's question down from inside the water without mercy.
Being under fourteen meant you could do almost nothing—more so than anyone who hadn't lived it could imagine. Even the card they used now wasn't in Mari's or Siyeon's name. It was issued as a "magical girl activity fund" card, good for checking the balance and making direct purchases, and that was it.
You couldn't transfer money to anyone online, and thanks to some ancient rule nobody could explain, magical girls were forbidden from using messengers with each other. The only real channel of communication between magical girls was the mascots.
Figuring that was answer enough, she started to get up again—only for the next question to land.
"And also. This is a house provided for a magical girl, isn't it? So why is there no air conditioner…?"
Hearing that, she first let out a short, flat "Ah."
From a mascot's point of view—people who wouldn't know the history of this place—it wasn't an unreasonable question. There were plenty of things the mascots assigned during the process of becoming a magical girl simply wouldn't know.
"There are complicated human circumstances involved."
Slave aptitude… or rather, stage one: discovering a magical girl's aptitude. Even that first step worked on a hand-me-down system—when the local magical girl's retirement approached, they found a successor and passed the role along.
Stage two was where things got ridiculous. A government-connected human with the right "connections" would buy one of the empty residences and present it to the incoming magical girl. The senior would retire, and the successor would be introduced to the press.
Most magical girls started young—as early as elementary school, and at the latest as middle or high schoolers. And they didn't buy a place someone had just vacated. They bought completely empty properties. Brand-new houses with zero trace of a previous occupant.
Then came stage three. During the school years, as long as food and basic living needs were covered, there wasn't much to spend money on. The people in charge knew that perfectly well, so they skimmed a portion of the activity fund paid out later and used it to furnish the house.
But how much were they supposed to know about which furniture was needed, how, or why?
Washing machine, bed, wardrobe, TV, and various other odds and ends—they'd been filling the place while whittling down the fund, when they made one enormous mistake.
They forgot the air conditioner.
Well, it couldn't be helped, okay?
Thinking back to that chaotic kindergarten winter, she ran a rationalization nobody was around to hear: it really couldn't have been helped. She'd only just realized she'd been reborn as a little girl—and then it turned out this was a world with magical girls. Suddenly they handed two elementary school kids a whole house and told them to pick out furniture. How sharp could her head have been?
And besides…
Back then, there weren't even that many options relative to the activity fund.
The furniture she had carefully chosen while enduring the pain of watching the fund get cut—that was everything currently in this house, air conditioner excluded.
Only after all of that came stage four: mascot assignment. So of course the two of them had no idea what process this house had gone through.
Recalling the whole chain of events, she decided she couldn't be bothered explaining any of it and let it go.
"Too annoying to explain."
"Eh."
That short conversation ended with nothing but the bear's lingering curiosity. After that, monster extermination settled back into its normal rhythm and went smoothly enough.
Not for the monsters' sake, but for her own: she dialed back the intensity of the torture to match the midsummer heat, just so she could get home even a second faster and sit under the fan. Faithful days like that rolled by—and at last, the long-awaited air conditioner installation day arrived.
"Your parents aren't home?"
"They said to install it right here!"
With practiced lies, she and Siyeon fooled the adults and smoothly got exactly what they wanted. The imaginary, completely irresponsible parents they'd invented were far more convenient to exploit than expected.
Parents who sent the kids on an errand to buy an appliance, then went clothes shopping. Parents who left two elementary schoolers alone at home while they went off somewhere. Neither version could be called remotely responsible—but right now, she felt nothing but gratitude toward those fictional beings.
Naturally, the technicians who came to install the air conditioner didn't need any special requests. They simply got to work. They opened up the back of the unit, ran the pipes, and connected everything to the outdoor condenser. Once the installation was perfect, they pressed the remote into her hands and gave a short rundown of how to use it, along with the manual.
"This is the temperature control, and if you only want it on for a few hours, press the clock button and set it from there."
That sensation—no cold-draft worry needed, the whole room growing far cooler than any fan even when you couldn't feel the wind directly. Her eyes lit up as she felt the formerly muggy room fill with cool air through her whole body.
They could have stayed to enjoy the breeze themselves, but once they'd collected the installation fee, they left with perfect cool. Watching the magnificent backs of those summer heroes as they opened the door and walked out, she almost snapped off a sharp salute.
And once the heroes had gone…
"Ahhhh, this is amazing—!"
"Kyaaah—!"
They immediately roared with pure satisfaction and started rolling around on the floor near the unit, where the cool air was strongest. Siyeon got so excited she didn't even hesitate to climb right on top of Mari—body contact and all, on a day this hot.
On a humid, sweltering summer day, even holding hands would normally send the discomfort index through the roof… or it would have, if the cool air hadn't already dried their sweat in an instant and erased both the humidity and the heat.
Performance so good that the seven-digit sum that had vanished in a flash didn't feel like a waste at all. Covering her mouth with both hands as if she might actually sob, she spoke that great name aloud.
"Thank you, Willis Carrier…"
"Will…?"
"No, you don't need to know yet."
Siyeon tilted her head at the muttered words, but Mari simply moved the hands covering her mouth over to Siyeon's back and patted her.
Ah, O Creator of the Air Conditioner. Once Siyeon was old enough to learn who he was, she would naturally come to worship him too.
With a little breathing room in her life at last, a thought finally surfaced.
Maybe I should do some of that homework already.
She opened the school bag she hadn't even thought about touching for days and pulled out the vacation assignments. First-grade summer homework—something you could finish with a day or two of halfhearted effort. She even filled in dates that hadn't arrived yet and padded out just enough volume to call the diary done.
The reading worksheet is the real problem, though…
Of everything, that was the one real snag. The only books in the house were textbooks. Which meant she actually needed to get her hands on a real book that wasn't a comic. Something educational, recommended reading for children—that sort of thing.
I don't want to read that either.
While Mari was, for once, genuinely struggling with elementary-school vacation homework, aboard the monsters' ship a regular training session was underway.
The instructor wasn't one of the monsters stationed on the ships near Earth. He was a renowned monster professor invited from a planet outside the solar system: Alteda. His body was like flawless metal, and across past and present he had defeated magical girls a total of ten times.
He had long since stepped away from the role of combatant bound for Earth, but by the standards of monsters who had steadily invaded the planet, he was still a formidable creature.
After the usual rundown of species-specific combat methods, they reached the free question period—which was allotted more time than the lecture itself.
"Alright then—any monster with a question about Earth?"
From among the countless raised tendrils, Alteda pointed to the one at the very front.
"Go ahead."
"Why are we not allowed to touch humans who aren't magical girls?"
"Ahh, that's an excellent question."
Along with his answer came a harsh clang of metal on metal—nothing more than parts of Professor Alteda's own body knocking together.
As if determined to properly explain the reason for such a good question, he carefully walked them through why "humans who aren't magical girls" were off-limits.
"In planet-to-planet conflict, it might seem only natural, you see. But if civilian monsters are attacked in the process, then even if you conquer that planet, you'll inevitably breed resistance. Even weak monsters, if they band together, can cause catastrophe—just look at the case of Planet A-7221."
The first explanation was that harming civilian monsters beyond the combatants during a conquest would fan the flames of vengeance beyond control, creating problems even after the conquest was complete.
And the second explanation that followed was, for him, the real core of it.
"We can hardly leave Earth's magical girls out of this, can we? In fact, there was exactly one occasion in the past when a non–magical girl human was harmed. And the price was catastrophic."
One of Earth's magical girls—rated the weakest of them all—had witnessed a civilian's death and, on the spot, "permanently erased" an executive-class monster in an instant. That incident was carved into monster history, remaining the first and last case in which even recovery devices had been rendered meaningless.
"Research into that case is still ongoing. Based on the circumstances at the time, we currently suspect a trigger that activates upon seeing the blood of one's own kind. Yes."
That was Professor Alteda's theory. Either way, until the reason was uncovered, the directive from higher up to every monster remained:
Absolutely never touch Earth's civilian humans.
That terrifying magic—which made even recovery devices useless—and the short-term explosive surge in a magical girl's power had been held up as examples of something that must never be allowed to happen again.
"Now then—imagine if that magic were learned by Sun, who's been such a hot topic even on this ship lately."
"……"
A hypothesis so chilling that even monsters who showed emotion through their skin would go pale. The monsters listening snapped their eyes wide open.
The permanent erasure of a monster—and Sun doing it?
That wasn't just a nightmare. That was the nightmare.
"We'd all be completely screwed—reduced to our reproductive organs. Hahah."
Professor Alteda laughed heartily, delivering an Earth-style joke. But the monsters who actually understood the impact of the Black Zone did not laugh. Instead, various bodily fluids simply slid down their throats with a heavy gulp.