Chapter 8: The Letter

One day, a single envelope arrived in the mailbox of Problem Solver 68’s office.

“Dear members of Problem Solver 68.
Let’s skip the formalities.
The reason I’ve gone out of my way to send this letter is simple: I’ve decided it’s time to put an end to this troublesome situation.
Please come to the coordinates marked on the attached map at exactly 3:00 p.m. today, the 21st.
In case anything happens, I will be taking your ‘friend’ as a hostage.
—From the Cleaner”

The handwriting was strangely elegant.

In the next moment, the letter was crushed into a tight ball.

“You’ve really done it this time… Cleaner.”

For once, the office was silent—so quiet that the heat in her voice felt even sharper.
When Sensei turned, he saw Al standing there, her voice blazing even as her expression remained frighteningly cold.

“I thought you were the pinnacle of outlaws—the person whose back I should be chasing. But I guess I was wrong. Taking such a fragile girl hostage… I’m honestly disgusted.”

“Al, calm down.”

“I am calm, Sensei. Perfectly calm.”

Even as she said that, her grip tightened around the crushed paper. She was absolutely furious.

“Fine then, Cleaner. We at Problem Solver 68 will defeat you and save Amari Komori. A petty coward who uses such dirty tricks doesn’t scare me! We’re going right now! Get ready to have your head handed to you! You two—prepare!”

“Y-Yes, Al-sama!”

“Can I bring all of this stuff with us?”

“Go ahead. Blow them away!”

“……”

“……”

“…What’s wrong, Kayoko? And you too, Sensei. We need to get going, you know?”

“…Al, about that… no, it’s fine. First priority is taking down the Cleaner.”

The place the Cleaner specified was right on the border of Gehenna Academy territory—barely inside or barely outside, depending on how you looked at it.
Even in Gehenna Academy, one of the largest schools in all of Kivotos, there existed a small number of areas referred to as slums.

There were no ordinary people around—only those who seemed to come from shady, dim backgrounds. Interference from the Prefect Team or police was rare. Truly, it was the perfect place for a final showdown.

Its only flaw? Distance.

“They didn’t… pick such a faraway location on purpose, did they…?”

Right now, the group was fully armed, being rocked back and forth on a train.
Their office and the designated coordinates were far—extremely far. So far that taking the train was the only way to make it in time.

“Once this is over, they’re paying for emotional damages and transportation costs! They’d better be ready!”

She shouted, but the others were unusually quiet—likely from nerves.
Al’s ability to remain her usual self even now was one of her talents.
…Or maybe she was just so blinded by anger she hadn’t fully grasped the seriousness of the situation.

“…Boss, calm down.”

“I am calm!”

“Then… did you notice anything strange?”

“Nope!”

“…Sigh.”

Seated beside her, Kayoko let out a sigh and pointed around them.

“Those passengers didn’t react at all even though you were yelling, right?”

“Huh? They just didn’t notice, maybe?”

“…Okay, then. This train is heading toward an area full of slums, yeah?”

“Yes.”

“Then doesn’t it seem… a little too crowded?”

“Now that you mention it… yeah, maybe…”

“And also, isn’t it just a bit—

—too quiet?”

“!?”

Clunk.

The moment she said it, the entire train lurched violently. And unless it was their imagination, the scenery rushing past the windows had gotten faster too.

“Sensei!”

“Yeah.”

Sensing danger before anyone else, Kayoko called out. Sensei immediately pulled out his tablet—the System Box.

The other members, shaken and confused, began shifting into combat readiness.

Yet strangely, the passengers remained seated as if nothing had happened. Even though Problem Solver 68 had drawn their weapons, none of them reacted. They simply sat. Unmoving. Still.

“…This isn’t good.”

“Could it be a trap~?”

“Seems like it.”

“Eh!? W-What do we do!? Should we blow everything away!?”

“C-Calm down! First, stay collected and assess the situation! That cowardly trap won’t scare us!”

Keeping watch on their surroundings, tens of seconds—or perhaps only a few seconds—passed in tense silence. Then, abruptly, something changed.

From the wall-mounted speakers, a sandstorm-like static hummed: “zzz, zaa—”.

And then:

“This train is bound for the ●● Line inner loop, heading toward ■■.”

A perfectly normal train announcement.

“…Phew. What is it? Just a regular announcement.”

“…Wait.”

“Next station: ▲, at #%, tu, zu, ts───”

“Eek!? W-What the—horror!?”

The announcement suddenly distorted. The calm, formal voice repeated glitchy, broken sounds—and then finally cut off.

Even in this abnormal situation, the passengers didn’t react. Not even a twitch. They sat perfectly still, like lifeless dolls whose strings had been cut────

“Zaza, za, za──ah, ahh, eh… to the customers aboard──members of Problem Solver 68.”

“!!”

The voice had changed.

It was flat. Terrifying. A voice that could instill fear in anyone who heard it. Only Sensei had ever heard it directly before.

“Welcome. To the battlefield I have meticulously prepared. My name is───”

“Cleaner, right?”

“…I would have preferred you not to reveal it before I officially introduced myself, Sensei.”

Clatter, clatter—the sound of the train echoed, now clearly faster than before.

“So you’re the Cleaner!”

“Indeed. I am the Cleaner. And you—are the ones who tarnished my signboard.”

“…Why did you involve that girl?”

“That girl…? Ah, no matter. She was the perfect decoy. I made use of her. I couldn’t risk you escaping otherwise.”

“We wouldn’t have run away anyway!”

“Isn’t that your convenience? I want to eliminate even the smallest uncertainties.”

“Then, now that we’re already trapped, there shouldn’t be a need for a hostage, right?”

“Sensei!”

“…True. But wouldn’t that be boring? Since it’s a special occasion, she will be the reward for when you finally defeat me. Though, of course, that will never happen.”

“……”

“Now then, shall we finally begin?”

Right then—

“Eek!? I-It started moving!?”

“…Whoa.”

“What is this? So creepy~.”

“Should I just kill them all!?”

“N-No, you can’t!? They’re alive!?”

“Uh, they’re shooting at us.”

The passengers—who until now hadn’t moved an inch—slowly rose with ghastly, puppet‑like motions. And from who‑knows‑where, they drew assault rifles and handguns, aiming them directly at Problem Solver 68.

“…Cleaner.”

“Hm? Ah. Don’t worry, Sensei. These are lifeless dolls I created. Feel free to destroy them.”

“Then that’s perfect! Wipe them out!”

“Y-Yes ma’am!”

“Ahahaha! Very spirited, aren’t you! But do you really think you can defeat my adorable creations so easil──”

RATATATATATATA!!

“──…N-Not bad at all.”

“Let’s go!”

Passenger puppets were blown apart one after another by shotguns and explosives. Even as the Cleaner’s confused voice crackled through the speakers, the girls advanced steadily down the aisle.

But then—

“—! Sensei!”

“!?”

Sensei stumbled, falling forward—just as something streaked past the space where his head had been a moment earlier. Not merely fast—light‑speed. A beam left a glowing trail behind it, and wherever it passed, metal melted as if seared by extreme heat, leaving holes in its wake.

“…A laser?”

“Correct. Spot on. Though I didn’t expect you to dodge it!”

“Whoa!? He’s shooting again!”

“He’s firing without caring who he hits—even his own dolls~!”

“Waaahhh!?”

“If that hits you, even you will feel it. Now then—do try your best to dodge. If you can, that is.”

A third shot.

The beam tore through anything in its path, friend or foe, carving out severe destruction with every pass. If this continued, even without a direct hit, the train car itself would be annihilated—and they wouldn’t survive that.

“—! Arona!”

【Yes, Sensei! I’ll display the predicted firing lines! Please do your best to dodge them!】

“…Alright, everyone. I’ll start commanding now.”

Time for the counterattack.