There's a sound you hear everywhere.

A thrumming sound.

The sound of the Mega-Engine. The driving force that powers this metropolis of London. That's what it's supposed to be, anyway.

A sound everyone is used to hearing.

A sound everyone takes for granted.

That sound has been continuous since the day I was born. Yesterday, today, and tomorrow, without change.

—Clang, clang

The doorbell attached to the shop door chimed.

“Welcome…”

I, the shopkeeper’s assistant, mumbled a halfhearted greeting.

It was the same as always. I used to get scolded for it, but the intimidating owner, who's known me for years, seems to have given up on trying to change me. So, it's always been like this.

Anyway, putting that aside.

That day, an unusual pair of customers came in.

Two men. One was a tall, middle-aged man with slicked-back gray hair and sharp, predatory eyes behind a monocle.

The other was his companion, a young man. A little older than me, with a sharp gaze and distinctive black hair.

The owner seemed to know the man with the monocle. Even though the owner was clearly older, he was surprisingly amiable (though still plenty intimidating).

Apparently, they had come to have a coat repaired. It was the young man who handed it over. I glanced at it sideways. It was an unusual, wine-red hooded coat. But what caught my eye more than the color was its condition. I wondered what he could have possibly done to it to get it into that state.

I mean, really. A perfectly round hole in the middle of a coat doesn't just appear out of nowhere.

The three men, including the young one, discussed various repair options for the coat. Something about "iron…" and "reinforcing…"

Before I knew it, their discussion had moved on to price negotiations. The owner and the older man started talking shop again.

The young man, excluded from the conversation, looked around the shop curiously.

I idly observed him. I had nothing better to do. There were no other customers, and as the shop assistant, I had no particular tasks, just sitting at the reception counter, bored.

“…You look bored.”

Suddenly, someone spoke to me. My chin resting on the counter, my reaction was a bit delayed.

I shifted my gaze to see who had spoken. It was the young man who had been looking around the shop.

“…Well, yeah. It's rare for customers to come directly to the shop.”

Since the Steam Engine Revolution, even clothing production has become mechanized, making handcrafted items extremely rare. In such a world, people who specifically come to a shop like this to order clothes are quite unusual. Especially those who actually show up in person instead of using the Engine Phone; we get maybe one a month, if that.

The owner of this shop was a rare craftsman in this day and age. However, he seemed to be somewhat famous, as occasionally important-looking people in expensive clothes came to place orders. Thanks to them, the shop managed to stay afloat, but customers were still a rare sight.

“Hmm. Guess it’s the same everywhere.”

The young man responded casually to my comment, leaning against the counter and turning his attention to the owner and the other man.

“Looks like that’ll take a while.”

“…Probably. I’ve never seen the owner talk so much.”

I trailed off, too lazy to finish the sentence. He chuckled, “If you’re going to say it, say the whole thing.”

I was impressed he noticed.

Well, I noticed, but I didn't say anything.

He also seemed to have lost interest, saying nothing more and just staring blankly at the ceiling.

“…Hey.”

“Hmm?” He responded without looking away from the ceiling.

“What happened to your coat?”

I asked, somewhat curious. There was a large, round hole right in the middle of it. I couldn't help but wonder how it got there.

He groaned in response, something unintelligible like, “Uh…” and “Hmm…” before finally saying,

“Let’s just say… I messed up on the job.”

“Huh.”

“You’ve got some nerve giving me a non-answer after asking.”

He said, looking down at me with half-closed eyes.

“I didn’t really get it.”

“Ah… Right.”

At my honest response, he scratched his head and sighed. Well, it couldn't be helped. I really didn't understand.

He said “job”—but I couldn’t imagine what kind of job would result in something like that.

Well, I just asked out of curiosity, so it didn't really matter.

As we were talking, the owner and the other man seemed to have finished their discussion. “Alright then, owner, I’ll leave it to you. Sorry to keep you waiting, Tobari. Shall we?” the man said to the young one.

“Yeah,” he replied casually, then said to me, “See ya,” before leaving the shop with the man.

Watching them go, I muttered, “Strange guy…”

Other than that unusual pair of customers, it was just another day at the shop.

The same as yesterday. And probably the same tomorrow.

Wake up, eat, work at the shop, go home, sleep—occasionally look after the younger kids in the back alleys.

The same thing, over and over.

A bit boring, but not particularly unsatisfying. My days continued, uneventfully.

The same yesterday, today, and tomorrow.

Yes.

It was supposed to be unchanging.

I believed that.

But—that day.

I saw it.

I learned it.

The terror that sound, the sound everyone takes for granted, can bring.

The despair that sound, the sound everyone is used to hearing, can bring.

It… appeared before me.

It was a mass of steel.

It was a mass of steam engines.

No, that's not right.

It was—

Undoubtedly, a grotesque monster.