After walking through the forest for several minutes under Yuta-san’s guidance, an old concrete rectangular structure with a heavy door came into view. A rusted plate was bolted to the door, bearing the grim warning: "Danger: Keep Out."
It certainly had a certain atmosphere—or rather, a distinctively unsettling vibe.
"This was built during the initial survey to provide access to the underground cavern. However, it’s been abandoned for years. The deterioration is severe, and as for the safety..."
"Well, looking at the state of this door, it’s clear no one’s been doing any regular maintenance," I noted.
"No. Once the survey ended, there was no reason for anyone to come down here. I only open the door a few times a year to make sure no trespassers have broken in."
"I suppose you can't risk someone wandering into the cave and having an accident," I said.
Finding a suspicious body in a cave beneath a resort under development would be a nightmare. Even though the resort project had already collapsed, a scandal like that would turn the site from a potential investment into the setting of a horror story.
"Fortunately, we’ve never had an accident of that nature."
"That’s a relief. It would be a real problem if we rented the place only for a body to turn up later."
"Haha, that would be just as much of a problem for us. Even if the victim were a trespasser, we’d still be held responsible for the management of the property. People would start asking why we hadn't sealed it off more securely."
"The fence around here is pretty old, too," I pointed out. "It’s got holes all over the place."
It was the kind of property that was technically managed, yet somehow felt neglected. Then again, reinstalling a massive fence to mark the boundary of such a large plot would cost a fortune. As long as nothing happened, they probably saw no reason to replace it.
As we spoke, Yuta-san approached the weathered door and set to work on the lock.
"True. But we make it clear that this is private property, and people don't exactly flock to this area anyway. If anything gets in, it’s usually just wild animals."
"Wild animals, huh? In a place with this much nature, I’m not surprised."
"The records from back when the resort plan was active showed no signs of large predators. Of course, a lot of time has passed since then, so the ecosystem might have shifted."
"I see. Still, there’s a fence, so I doubt anything too large is living inside."
"I hope you’re right... Alright, it’s open."
Yuta-san unlatched the lock and pulled. The door, stiff with rust, swung open with a high-pitched, grating screech. Immediately, a rush of cool, damp air spilled out from the darkness beyond.
It seemed this door really did lead straight into the earth.
"The cave interior lies just ahead. But as I mentioned, the stairs are badly dilapidated. I can’t guarantee their safety."
"...Yeah, looking at this, 'dilapidated' is an understatement."
The stairs before us were a rudimentary setup made of metal scaffold pipes and steps, the kind seen on construction sites. Rust had bloomed across every surface, and in several spots where the corrosion was particularly advanced, the metal had crumbled away entirely, leaving gaping holes.
If someone told me to use these stairs, I’d have flatly refused. You never knew when the whole thing might give way.
"Just to show you..." Yuta-san reached out and gave one of the main scaffold pipes a light shake.
The entire structure, despite being made of metal, began to sway violently. It emitted a series of sickening groans and sharp, snapping sounds like something was about to fracture.
"Whoa, that’s... that’s not good."
Yeah, there was no way I was setting foot on those stairs.
"As you can see, they’re practically useless."
"Definitely. At this point, it would be safer to just tear them out and start over," I suggested.
"That’s the thing," Yuta-san said with a pained expression. "Since there was no plan to use the facility, the decision was made that as long as the door was locked, it wasn't worth the budget to remove them."
"I guess that makes sense from a business perspective, if you aren't using the place."
We stood there, frowning at the crumbling metal, while Yuta-san explained the budgetary constraints. It was a classic case of abandoned infrastructure—not worth fixing, but not worth the cost of disposal either.
"Anyway, because of the state of the stairs, we can't actually go down. If you wanted to see the interior, we’d need to come back with proper equipment..."
"Yuta-san... how many meters is it to the bottom?" Yuji asked.
"Eh?"
"It’s a bit dark, so I can't be certain, but it looks like about five meters?"
Yuji was leaning past Yuta-san, peering into the gloom and gauging the distance to the floor below. Yuta-san looked confused for a moment, then seemed to remember exactly who he was dealing with. He paused to think, searching his memory for the survey data.
"The documents I saw said... yes, a little over five meters, I believe."
"Five meters... That won't be a problem," Yuji said.
"...Just so I’m clear, when you say 'no problem,' are you talking about jumping down?"
"I mean for getting up and down in general," Yuji clarified.
Yuta-san’s eyes went distant for a second as he processed that, but he quickly regained his composure and offered a warning.
"Look, Hirose-kun. I’ll take your word for it that the distance isn't an issue, but we didn't bring any gear today. I don't even have a flashlight. Surely even you wouldn't just dive into a pitch-black cave where you can't see your footing?"
"True, not being able to see the landing zone is a problem... but as long as you're okay with it, Yuta-san, we can solve that pretty easily."
Yuta-san fell silent at Yuji's suggestive tone, his gaze shifting between us as he carefully weighed his words.
"Does this involve those unique explorer abilities... skills? I thought using skills outside of dungeons required permission from the Dungeon Association or the government?"
"Offensive skills like magic are restricted to authorized areas like training grounds, but the use of non-offensive skills is a bit of a gray area," Yuji explained, his tone becoming technical. "Skills are divided into active skills, which you trigger intentionally, and passive skills, which are always on. Because of that, the law can't just issue a blanket ban on all skill use outside of dungeons. Generally, the rule is that using a skill to commit a crime carries much heavier penalties than normal. Essentially, it boils down to: 'Don't use them to cause damage or break the law.'"
"I see... That makes sense. So, the skill you’re planning to use is..."
"It’s called [Light]. It’s a spell we use to maintain visibility inside dungeons. It’s a very convenient light source."
As he spoke, Yuji activated [Light]. A glowing orb of mana appeared, and he sent it floating through the doorway to illuminate the descent.
"Whoa... Seeing it lit up like this really drives home how bad those stairs are. This is dangerous. It wouldn't be surprising if they collapsed under their own weight."
The scaffold pipes had looked bad enough in the dim light from the door, but under the brilliant glow of the [Light] spell, the true extent of the decay was revealed.
While the four main support pillars seemed to be holding up—barely—the clamps and fittings connecting the pipes were a disaster. Most were encased in thick crusts of rust, and several had corroded so completely they had snapped, leaving the horizontal pipes dangling or lying on the ground. That was why the whole thing had swayed so much when Yuta-san touched it.
"Those stairs are a total loss," I said. "If anyone tried to put their weight on them, they’d go down with the whole structure and get seriously hurt."
"I agree. I didn't realize it had gotten this bad," Yuta-san admitted. "I’ll have to report this to the President. Honestly, it might be better to just fill the entrance in entirely."
Filling it in was certainly one way to handle the liability if they weren't going to rebuild.
We decided to leave the matter of the stairs for a later discussion with Kiritani-san and focused on getting down into the cave. The rickety structure was in the way, but there was enough space to bypass it.
Yuta-san, unable to make the climb himself, agreed to wait at the top while the three of us explored the interior. He made us promise to keep the survey to fifteen minutes and to stay within sight of the entrance.
"Alright, Yuta-san, we’re going to take a look."
"Please, be careful. I’ve only seen the old survey maps; I’ve never actually been down there myself. I have no idea what the conditions are like. I’ll call out when the time is up, so come back immediately."
"Understood. We aren't planning to go deep without proper gear. We just want to see this 'great cavern' that supposedly killed the resort project with our own eyes."
"We’ll just take a peek and be right back."
"Today’s just a site visit, after all," I added with a small smile.
We reassured the worried Yuta-san, knowing that since this wasn't a dungeon, we wouldn't be running into monsters or traps. It was still an unmaintained cave, so we couldn't be careless, but it wasn't the kind of danger we were used to.
After a final nod to Yuta-san, we checked the landing and jumped down into the darkness.
"See you in a bit, Yuta-san!"
"Be careful! Don't get hurt!"
We landed with light thuds and gave a quick wave to Yuta-san, who was peering anxiously down from the concrete entrance. The passage at the bottom was wider than I’d expected. The floor was uneven and rocky, making for awkward footing, but it was easy enough to navigate.
"Not to state the obvious, but this is a very cave-like cave. If we leveled the floor with some Earth Magic, we could turn this into a perfectly good hallway," Yuji suggested.
"We’d need to set up some permanent lighting, but the space itself is great," I agreed.
"We should probably think about dehumidifying it, too," Hiiragi noted. "Being by the ocean, the air feels thick and heavy against my skin. It’d be a lot more comfortable if we could dry it out a bit."
As we walked through the passage, brightly lit by Yuji’s [Light], we were already brainstorming ways to renovate the space.
The truth was, we had already taken a serious liking to this property.
"In a place like this, we could practice any skill we want without having to worry about prying eyes."
"Exactly. The whole reason we were looking for remote land was to keep our training private. That’s why we asked for something isolated, but..."
"If we’re underground, all we have to do is secure the entrance and nobody can see us. No neighbors, and no drones or satellites peeking from above either."
This property hit every single one of our requirements. The fact that the surrounding land was uninhabited was a huge plus, and while the access road was a bit rough, it was still functional. We were even within delivery range for home centers and hardware stores, meaning we could get all the supplies we needed to build our training ground.
As far as we were concerned, this was the most promising rental property we’d seen.
"We should be reaching the main cavern Yuta-san mentioned soon..."
After walking for a few minutes from the entrance, the passage opened up, and we stepped out into a vast, empty void.
To truly evade surveillance from above, the only real options are underwater or underground... and we had just found our subterranean sanctuary.