The moment we heard Mist's words, the landscape in front of us had changed.
　What I saw was not the guild's room that I had seen earlier, but the scenery outside.
　After looking around and confirming that this is outside the labyrinth city, I muttered softly.

''...... a real transition camp?''

　It wasn't that he suspected that the transference formation Mist was using might be fake.
　Still, I couldn't help but feel a sense of wonder at actually using the transference camp outside of entering and leaving the labyrinth like this.
　...... Once again, the awe of lost technology is etched into me.
　However, I shake it out of my mind that now is not the time to be distracted by lost technology.
　The top priority is to deal with the current situation and there is no time to worry about anything else.
　And I know that I need to be more sure about this than the transfer team.
　For now, I'm going to ask Master in front of me for confirmation.

"...... Does Master know about the existence of the thing Myst was talking about?

　It was too wordy a word to call it a question.
　But that was enough for now.
　I confirmed that everything I wanted to say was conveyed to the master who silently shook his head, and I held my tongue.
　After all, this is not a story that I am the only one who doesn't know.
　Convinced that something is obviously wrong, I ask Mist.

What do you mean by the walls of the labyrinth city?　...... There shouldn't be any walls in a labyrinth city.

　I distinctly remembered what Mist had told me before the transfer.
　No, I couldn't forget them, because even though they were always on our minds, they weren't there.
　Because even though we were always craving for it, what we didn't have was the wall.
　Therefore, I can't hide my distrust of the mist that treats the walls as something that exists.

"There are no city walls in the labyrinth city?

　...... At my words, the expression on Mist's face was at odds with his previous aloofness.
　It's a complicated expression, as if she was nostalgic, reminiscing, and regretting something.
　I was blindsided by Mist's appearance, which was so different from what I had seen before.
　But that expression was gone the next moment.

''It can't be helped. It's the role of an old man to teach a young thing about the past. I'll tell you about it along the way. Why doesn't the labyrinth city have walls like Nelburg?''

　Mist tells me with a smile on his face, as if he wondered if he had seen the expression he had just given me wrong.
　I wonder if I've misjudged her expression, the thought comes to me.
　But as Mist starts to walk, I shake that thought from my mind once and decide to follow her back.
　As he walks, Mist begins to speak.

Well, to put it simply, it's useless. Walls like the one in Nerburg are so fragile that a slightly better wizard could crush them. Where such a thing existed, it would quickly crumble in a labyrinth runaway and be over.

　That was certainly true.
　In a labyrinth runaway like this one, they would be destroyed in no time.
　In a labyrinth runaway, Rich would unleash a tactical-grade magic technique.
　Under such an attack, the city walls would be shattered in a single blow.
　Still, I didn't think it was good to be without.

''Therefore, how can you conclude that it's good to not have the city walls!

　I inwardly agree with Narcena, who distorted her face and spat it out.
　Yes, even if the walls can only withstand a single blow, they are not meaningless.
　No matter how fragile the walls are, on the contrary, they are able to withstand a single blow.
　The significance of that blow is huge.
　And even if they collapse, they can be used as a defensive battlefield in the fight against monsters.
　Even if the walls are fragile, it's obviously better to have them, even if they're fragile, I was about to spit out in frustration, but before I could, Mist spoke up.

We haven't come to the conclusion that we don't need the walls. The policy we decided on then was to build a wall that could withstand a labyrinthine runaway.

...... Huh?

Isn't it obvious?　How much of this labyrinth city do you think has been put in place against the labyrinth runaway in the first place?

　Saying this, Mist pointed to the transition camp we had just crossed over.

'The transition camp that allows you to enter the labyrinth even from the labyrinth city, and the preferential system for adventurers in the labyrinth city. All of these mechanisms are designed to keep the labyrinth of the labyrinth city from running out of control, and to minimize the danger if it does run out of control.

　Laughing as if he enjoyed our reaction, Mist continued to speak.

''How could this labyrinth city, which is so well-protected, not have walls?

　Suddenly Mist stops walking.
　For a moment I brace myself for a moment, wondering if something has happened.
　But when I saw Hanzam out of the corner of my eye, I soon realized that this is where Mist was headed.

　This is where Mist was headed.

　Seeing that everyone, including me, realized this and stopped, Mist pointed to something.

''That is the wall of this labyrinth city, the highest wall.

　It's a white structure that surrounds the labyrinth city, a white structure that adventurers call the high ground.

...... what?

　I stared at the structure, stunned.
　It is true that there is something mysterious about it, and it is a beautiful structure.
　But that's all.
　It's impossible to stop a magical beast from avalanching into the labyrinth city with such a thing.
　It wasn't just me, Ronald-san and Narcena were also casting suspicious eyes at the Mist.
　Among them, only Master was different.

''So that's what it is. d*mn!　...... I should have realized this earlier.

　Spitting out his frustration without hiding it, Master puts his hand on the structure.

''Sh, Master!''

　I yelled out at the sudden action, but Master didn't respond.
　But, silently, he just begins to pour magic power into the structure.
　...... I came to understand that the master's action was the answer to my question.

　The next moment, the building starts to shine in response to the master's magical power.
　The light grew stronger and stronger, and after emitting an extremely strong light, the light spread out to cover the labyrinth city and its surroundings.

''This is the wall of the labyrinth city ......?

　And after the light subsided, what was there was a stone city wall that surrounded the labyrinth city.
　Seeing this, I finally understand.

　The city's walls were created by something magical, and this structure is the magical tool that activates the walls.

　Mist mutters with a rare look of astonishment.

'...... You think you have enough magic to create a barrier by yourself?'

Shut up.

　Fatigue was indeed evident on his master's face.
　However, that would be no surprise.
　The walls surrounding the labyrinth city were about ten meters high.
　If it was just after building such a thing, it was no wonder he was tired.

''Are you okay?　I'll give you a hand.

　Mr. Ronald extends his hand to his mentor.

'No, thanks. That's not the point, I've got more questions for the Mist.

　But the Master pushed his hand away and glared at Mist.

''Mist, let me ask you. What are these walls?　What do you want?

　Suddenly, the master reveals a hostility that has never been seen before and bites into the mist.
　We stand there dumbfounded by this transformation.
　But Mist, who is supposed to be facing hostility from his master, doesn't seem upset.

''If you don't calm down, I can't talk to you either?''

...... Shut up. I don't have the time or inclination to listen to you waste right now.

Mr. Larma, please calm down!

　The master, who was even more agitated by Mist's attitude and was exuding a killing intent, was appeased by Narsena, who decided that this was indeed too much.

''Narsena, it's this elf that you should be wary of.

...... Huh?

　Narcena, who was trying to appease the master who clearly assured him, stops moving.
　Master spits out while pointing at the walls covering the labyrinth city.

''Although it looks different, this is the same barrier that covered the neighboring city of Nelburg.

　The walls of the labyrinth city, at first glance, appear to be a simple wall of stone.
　However, when I detected the magic power, I realized that it was clearly not made of stone.
　At first glance it looks like stone, but this wall is a mass of magical power.

''Yes. This wall feels like stone, but its strength is obviously extraordinary. It's probably as strong as the ones made in the neighboring city of Nerburg.

　Before we know it, Ronald, who was lightly tapping on the city walls, assures us so.
　The master confirms that we've learned of the barrier's anomaly and glares at Mist with open hostility.

'So, Mist. When I built this wall, I noticed that it is similar in nature to the one that covers the neighboring city of Nerburg. ...... Hey, is that you?

What are you talking about?

　Mist's expression doesn't change as he smiles, aloof and unchanged.
　Looking straight at such a Mist, the Master asks.

''Did you create the barrier that keeps the labyrinth city isolated?

Oh, yeah.

　Mist laughs at his master's words.

'That's right. I isolated the labyrinth city.'

　...... And Mist easily admitted that he was the enemy.