Low-Melting-Point Metals

“So, have you already figured out how they’re smuggling everything?”

“All we have is circumstantial evidence. I don’t particularly like building theories on top of assumptions, though.”

Tōru thought it was impressive that Mary had managed to formulate a theory, however tentative, after just one evening of questioning people. Still, he decided to reserve judgment until he heard what she had to say.

After all, there was no guarantee she wouldn’t come out with something completely outrageous.

Mary wrote several pieces of information on a sheet of paper.

“First, let’s assume the smuggled goods are gold coins and silverwork. Since these are the items that have been disappearing or appearing mysteriously, we can be fairly certain about that.”

In other words, the smugglers needed a means of transporting both types of goods.

“The biggest obstacle to smuggling is finding a way through the walls surrounding Darandy. The city’s auTōruities have been aware of the smuggling for quite some time and have tightened security at the checkpoints, but they still haven’t managed to catch anyone.”

There were numerous methods of smuggling goods.

Containers could be modified with false bottoms or hidden compartments. People or animals could be made to swallow contraband, which would then be retrieved afterward.

Another method involved concealing goods inside candles, which remained in demand because magical lighting devices were still expensive despite becoming increasingly common.

“Darandy’s auTōruities must have already investigated these conventional methods.”

“Have you and Euphie checked them too?”

“We’ve examined the Ubaz Merchant Company’s transport wagons for modifications, as well as its merchandise and crates for hidden compartments. We found nothing.”

If even Darandy’s experienced guards couldn’t uncover the method, the smuggling operation must have been fairly sophisticated.

Mary continued writing smoothly across the paper.

“Now then, when Demon Centipede escorts the Ubaz Merchant Company’s shipments, what do you think they could carry without attracting suspicion?”

“Weapons?”

“Yes, weapons would be one possibility. There are Monsters and Magical Mechanical Beasts outside the city, after all. But that’s not what I’m thinking of.”

“Their Magical Prosthetic Arms and Legs?”

“Exactly. That’s what we should be focusing on. There’s also the matter of the Magical Prosthetic Arm you picked up this morning, Tōru-san.”

The twins’ observation reminded Tōru of how peculiar that incident had been, although he still couldn’t figure out why someone would deliberately leave a Magical Prosthetic Arm in an alley.

Besides, Tōru thought.

“Come to think of it, something felt strange when I picked up that Magical Prosthetic Arm.”

“Something strange?”

Mary looked at him expectantly, hoping he had recalled some new information, but Tōru made an apologetic expression.

“I was pretty drunk at the time, so I couldn’t figure out exactly what felt wrong.”

“…Did you notice that strange feeling when you looked at the arm?”

“Hmm? No, it was after I picked it up.”

He had certainly thought the Magical Prosthetic Arm was rather crudely constructed, but that wasn’t the same as the vague, unidentified feeling that had bothered him. Its poor craftsmanship was something he could clearly describe.

Nor had it been a problem with its performance, such as stiff or poorly functioning joints.

Nevertheless, he had definitely sensed something unusual.

Mary began flipping through the book lying open on her desk, searching for something as she tried to help Tōru remember.

“Perhaps it was heavier than an ordinary Magical Prosthetic Arm.”

“The weight, huh? I did think it was heavy, but the weight of a prosthetic arm depends on its construction, doesn’t it? …Ah, wait. I get it.”

Having finally realized what had bothered him, Tōru looked down at his own hands, which were covered by his chainmail gloves.

“Did you figure something out, Tōru-san?”

“…There were coins inside that Magical Prosthetic Arm. They were embedded in the thick metal plates covering the back of the hand and the outside of the forearm, which also served as armor.”

“Wait a moment. You mean inside the metal plates themselves, not in the gaps between the components?”

“Don’t ask how I figured that out. It’s directly connected to my fighting style, so don’t tell anyone.”

“Euphie will know, you realize?”

“So you really can’t keep secrets from each other, huh?”

“There’s no need for us to.”

Mary smiled brightly and held out the book she had been reading.

“I don’t know how you managed to discover that, Tōru-san, but we were also considering the possibility that gold coins had been embedded in the metal plates of that Magical Prosthetic Arm. You wouldn’t be able to tell they were there just by looking at it. In fact, there’d be no reason to suspect anything in the first place.”

The page Mary showed him was headed Low-Melting-Point Metals.

“What, you mean mercury?”

“No, alloys. Unlike mercury, they’re solid at room temperature. Their melting points vary, of course.”

Mary pointed to a table listing various low-melting-point alloys.

Among those Tōru recognized was solder, commonly used for joining pieces of metal together.

“Some low-melting-point alloys can be melted simply by pouring hot water over them. Wood’s metal, for example.”

“Hot water? …Ah, so that’s why Demon Centipede uses so much firewood.”

Wood’s metal was an alloy with a melting point of approximately seventy degrees Celsius.

Considering that agar generally melted at temperatures of eighty-five degrees Celsius or higher, that was an unusually low melting point for something metallic.

At that temperature, gold coins could be embedded inside a Magical Prosthetic Arm without any specialized equipment. All someone needed to do was place the gold coins on a base plate and pour molten Wood’s metal over them. The gold coins themselves wouldn’t melt or otherwise be affected, and they could easily be retrieved later by pouring hot water over the alloy.

What an interesting metal, Tōru thought admiringly as he examined the composition of Wood’s metal.

“Lead, tin, cadmium? Bismuth? Hey, lead and tin are one thing, but cadmium and bismuth aren’t exactly easy to come by, are they? Even I only remember seeing those two elements mentioned in supplementary chemistry materials back in high school.”

“That’s true. But I didn’t expect you to get hung up on something like that, Tōru-san.”

“What do you mean, hung up?”

“Tōru-san, surely you haven’t forgotten who you are or what kind of book this is?”

Mary tilted her head, sending her golden hair flowing gently as it reflected the light from the magical lighting device.

As Tōru gazed into her clear blue eyes, he realized where the Wood’s metal must have come from.

“A Fallen Object?”

“Exactly. Although I doubt they have very much of it. If they had a substantial quantity, they would probably make hammers or large magical devices to conceal bulkier items. They could even place highly liquid assets, such as gemstones, inside wooden boxes and encase the entire boxes in Wood’s metal.”

“So they only have enough Wood’s metal for transporting a few gold coins at a time to be the most efficient option?”

“Yes. And since Demon Centipede is an adventurer clan, there’s a good chance they discovered a Fallen Object in a dungeon.”

Fallen Objects were believed to appear most frequently in dungeons. Although they occasionally appeared outside dungeons, as Tōru himself had, the conventional wisdom was that anyone searching for Fallen Objects should explore dungeons.

Mary closed her book.

“Fallen Objects have caused all sorts of disturbances throughout history, but it’s rather exciting when something like that happens so close to home.”

“What’s exciting about it? We’re talking about a crime.”

“There’s nothing wrong with Fallen Objects themselves. The people misusing them are the ones at fault.”

Mary covered her mouth with a hand as she yawned, then continued.

“Which is why we should teach them a lesson.”

Mary handed Tōru the sheet of paper on which she had recorded their conversation and asked him to pass it to Euphie.

Mary climbed into bed at almost the exact same moment Euphie sat up.