"Hmm... I thought there'd be something here, but there's nothing in particular."
Rei muttered to himself as he walked through the mansion.
He had been fully convinced that people of similar strength to the Old Man from earlier would come at him, so not being attacked by anyone at all was completely unexpected.
"Could it be that there's no one else in the mansion? ...No, it's a base, so that can't be right. ...Oh."
Spotting a door ahead, Rei quickened his pace.
Even though it was a fairly spacious mansion, it wasn't any larger than those in the Noble District.
...Though exceptions did exist, like Marina's house.
Because of that, the number of rooms wasn't all that large, which was exactly why Rei thought he might be able to find some kind of clue without taking too much time.
Arriving at the door, he gently reached out... but stopped before touching the doorknob.
There's no trap, right? ...It's a door inside a base, so I can't imagine they'd go so far as to set a trap here. At times like this, it'd be really convenient to have Byune around.
Even so, he judged that there probably wasn't a trap and reached for the doorknob once more.
He kept himself ready to react immediately if anything happened, but fortunately, no needles shot out of the doorknob, nor did electricity surge through it the moment he touched it. The door simply opened.
Relieved, he moved to enter the room... or rather, before doing so, he checked for anything suspicious.
The reason he was being this cautious on this particular occasion—just as he had been with the doorknob—was solely because the mastermind behind the Cobolt incident was undoubtedly an extremely careful person.
Otherwise, it would be impossible for there to be absolutely no clues surfacing this far into the investigation.
Strictly speaking, there had been a few leads, but they had all gone cold before he could reach the mastermind.
Given that the opponent was that cautious, if this was a true base rather than a disposable one like the hideout Gran had known about, it wouldn't be strange for some kind of trap to be set.
Fortunately, there was no trap this time, so Rei stepped inside.
"A study... huh? How tedious."
There was a desk with bookshelves surrounding it, small though they were.
Books were fundamentally expensive items, so the ones here alone might not amount to a fortune... but they would certainly be worth a fair sum.
At the very least, whoever's using this base isn't hurting for money. ...Well, the fact that they prepared this base in the first place already made that obvious.
Whether this mansion was rented, purchased... or used without permission was something Rei didn't know. But using a mansion in this kind of location naturally meant there were inevitably various expenses involved.
If they were only staying for a very short time, that would be one thing, but living here for any real length of time made those expenses essential.
...Though that didn't mean he was envious or anything.
If you're the type to enjoy displaying Magic Items and the like, maybe you'd need a place like this. But for now, I have no need for a large mansion like this.
Thinking this as he eyed the desk, Rei began searching for anything that might serve as a clue.
However, the top of the desk was neatly tidied, and there were no immediately obvious clues—documents or otherwise—anywhere to be found.
Checking the desk drawers, he discovered a few sheets of paper, but none of them appeared to be particularly important.
"Given the location, I'd assume this study is meant for the master of the mansion to use, but there's no evidence of that sort here at all... What does that mean? Well, it could just be that while this is an enemy base, it's not their headquarters."
Rei hadn't expected to immediately find the kind of Magic Item he was searching for.
But even so, he had thought it wouldn't be strange for there to be at least some clue leading to one, so this was a complete letdown.
...The existence of a Magic Item was merely wishful thinking on his part, though.
"It doesn't have to be a Magic Item. It'd be fine if there was something else that looked the part... What do you think?"
"!?"
Hearing Rei's words, someone outside the room realized they'd been spoken to and caught their breath.
But as if immediately steeling their resolve, they burst in as if kicking the door down, and within seconds, located Rei and charged at him.
The fact that it took several seconds to confirm Rei's position was likely reason enough to call this person inexperienced.
For someone of a certain level of skill—such as the Old Man who had ambushed the Guards at the entrance and been effortlessly defeated by Rei—the time needed to spot Rei upon entering the room would have been an instant.
Several seconds versus an instant.
Viewed objectively, there didn't seem to be much difference between the two, and that was a fact.
But in combat, that gap became immeasurably vast.
And in practice, within this very fight, that slight difference proved fatal.
Rei had been waiting with Full Preparation for the charging attacker. His strike sank effortlessly into the man's solar plexus, knocking him unconscious on the spot.
However, the momentum from his charge couldn't be so easily stopped by a single blow, and the man crashed spectacularly into the desk with the same force he'd carried from his fall.
"The fact that this guy attacked me means the others are being attacked too? Even so..."
Rei focused his hearing, but no sounds of combat reached him.
While Rei's hearing was superior to a normal person's, it wasn't as sharp as Set's.
If they were fighting while making loud noises, he would have been able to hear it.
But if a battle began quietly and ended quietly—for example, if the Guards were being silently taken down in a surprise attack—he wouldn't be able to catch the sound of bodies hitting the floor.
As a countermeasure, the Guards were moving in groups of two or three, but even that couldn't guarantee absolute safety.
If these were ordinary criminals, it would probably be fine, but...
For now, since I don't hear any sounds of commotion, let's assume they haven't been attacked. In that case, the question is why this guy came after me...
He looked around the study, searching for anything that might explain it.
If there was something in this room that absolutely couldn't be seen, the attacker might have struck to keep it hidden.
That was what Rei thought, but the study was fairly spacious. It only didn't feel that large because of the sheer number of bookshelves.
"Could there be something inside the books?" Rei muttered.
Even in the manga, anime, and novels he had read back in Japan, it was common for bookshelves to have some kind of mechanism built into them.
The kind where pulling specific books in a certain order opened a hidden door had stuck in his memory.
But considering the number of bookshelves and books in this room, pulling off something like that would be no easy task.
In the first place, there wasn't enough time for that kind of search. If there really was a mechanism in the bookshelves, the only thing he could do was leave it to the Guards.
"Which means..."
He immediately gave up on the bookshelves and once again surveyed the room.
Before that, however, there was also the possibility that if the attacker regained consciousness, he would come at Rei again immediately.
To prevent that, Rei tied him up with rope from his Misty Ring so he couldn't move.
...Though since he wasn't a professional like the Guards, it was possible that a professional might be able to use Rope Escape.
In any case, after binding the attacker's hands and feet, he took another look around.
"Hmm... what about this?"
What caught his eye was an ornament placed on the desk—a small wooden statue carved from some kind of wood.
Rei picked up the statue, which was about palm-sized, but naturally, nothing happened.
"Do you place it in a specific spot? No, but would they really make something like this a key and then just leave it tossed on the desk?"
In the end, that was the conclusion he reached, and he set the wooden statue back on the desk.
"I feel like it'd be faster to just ask this guy directly. ...Setting aside whether he'd actually answer, that is."
At the very least, the Old Man he had fought earlier had shown no signs of cooperating whatsoever when Rei and the Guards had tried to extract information from him.
This attacker was undoubtedly less skilled than that Old Man, but the possibility that he was tight-lipped was more than high enough.
Well, I guess I should leave interrogation to the Guards. That's their specialty.
Thinking that, he once again surveyed the study.
Rei was neither a professional like the Guards, nor a Bandit, who could be called a professional in an entirely different sense.
Because of that, he didn't know the theory of how and where to search a study. So rather than following a method, Rei relied on his own intuition as he scanned the room.
Was there any place that felt somehow off?
Looking around with that thought in mind... he suddenly stopped.
What lay in his line of sight was a single painting.
Rei was fatally ignorant when it came to the arts, but even so, he could tell that the painting was skillfully done.
It wasn't a scene of Gilm, but a painting of a sandy beach and the sea.
At first glance, it appeared to be nothing more than a well-executed painting, but even so, Rei felt something was off about it.
What is it? What's bothering me?
Even as he thought this, he knew he wouldn't find the answer without investigating the painting itself, so he quietly approached the wall.
Standing before the painting, it was only then that Rei realized what had been bothering him.
"The... sense of distance is wrong?"
As his mutter suggested, the wall where the painting hung seemed one or two steps farther away than it had appeared from near the center of the study.
The difference wasn't all that significant, but even one or two steps meant a discrepancy of nearly a meter.
If so, the question of why that was the case nagged at him.
Is the painting itself a Magic Item? Ah, but there's a technique that uses visual effects to deceive like that. I think I saw something about it on TV back in Japan. Is it that?
So-called optical illusions, or trick art.
Not a Magic Item, but a painting created purely through skill.
Impressed, he thought it might be something of that nature, and with that understanding, he looked around once more...
"Hm?"
Something suddenly caught his eye.
On a different wall from the one where the painting had been hanging, there was now something that looked like a switch—something that hadn't been visible before.
It wasn't particularly conspicuous. In fact, it blended right into the wall's color.
It was camouflaged with a kind of protective coloring—something that never would have been found had Rei not been standing in front of the painting.
"What is this... what were they thinking, doing something like this? Well, they hid it this cleverly, so I suppose it means they didn't want it to be found."
Muttering, he approached the wall with the switch.
"Yeah, it's definitely a switch."
A so-called push-button type switch.
Since they had hidden it with a kind of protective coloring, it was only natural that they'd make it a shape that was easy to conceal.
If it had been a lever-type switch, for example, even if they'd tried to camouflage it by matching the wall's color, it would have been easily discovered.
"...And so, the biggest question is this: whether I should press it or not. I wonder. I think it's probably fine, but..."
A switch hidden in a place like this—not conspicuously displayed, but deliberately concealed.
It was highly likely that pressing it would open a hidden passage.
But at the same time, when asked whether an opponent this cautious would go out of their way to prepare a switch leading to a hidden passage—even one concealed with protective coloring—Rei couldn't honestly say yes.
Some kind of attack might be unleashed on whoever carelessly pressed it.
Or, pressing it might reveal some secret of this mansion.
Both seemed equally plausible, which was why he hesitated over what to do... and in the end, Rei decided to quietly call for the professional Guards.