Watching the drone take flight, I peered over Yuji’s shoulder at his tablet screen. Hiiragi-san kept glancing our way with curiosity and longing while she maintained her perimeter watch. Since her job was sentry duty, looking was all she could do for now.
Once I’d seen enough, I planned to swap roles with her.
“Wow, look at it go. It’s surprisingly stable.”
“Didn’t I tell you? A little hop like this is easy. The automation is so advanced these days that anyone can fly one if they’re just making it hover. You two should give it a try later.”
“Yeah, let’s test it out once we’re out of the dungeon.”
Yuji encouraged us to try our hand at it while he manipulated the controls. I agreed lightheartedly, my eyes glued to the tablet. I was genuinely interested, so I had no intention of turning him down. Of course, conducting a training flight inside a dungeon would be a bad idea given the constant threat of monsters.
I figured I’d wait until we were back on the surface. Since we were deep in the mountains, we wouldn’t be bothering anyone or running afoul of drone regulations as long as we stayed away from the crowds near the entrance... probably.
“First, I’ll take a quick loop around this area.”
“Right, thanks.”
If we suddenly flew it all the way to the stairs and it got swiped by a trap or a monster, it would be a total loss. First, we had to fly it nearby where we could see it clearly to check the ceiling for any anti-air traps.
If the drone got shot down, I’d have to start watching the ceiling as well from now on...
“Okay, here goes.”
Following Yuji’s commands, the drone tilted its frame slightly and glided through the air.
As we monitored the live feed, the screen showed an endless expanse of long grass. Honestly, it was a pretty tedious view.
However, once Yuji tilted the camera downward, the perspective changed entirely.
“Oh, there they are.”
“I’d hoped this would work, but it’s actually really clear.”
The footage on the tablet perfectly captured the figures of Grass Lizards lurking in the shadows. Their tough-looking skin stood out with a strange texture that didn't quite blend into the grass when viewed from above, despite their camouflage.
From this bird’s-eye view, it was obvious that something was hiding in the small gaps within the grass.
“The camouflage makes them a little tricky to spot, but this is more than enough.”
“Yeah. Our main goal is just finding the stairs to the next floor anyway, so this is a nice bonus.”
“It looks like they cluster near the stairs, so if we can get a general idea of their numbers and locations, we’re in business.”
The results of the drone reconnaissance were excellent. As long as it didn’t get shot down, we could definitely keep using this method.
“Alright, shall I fly it toward the stairs next? You okay with that?”
“Yeah, please. There’s no point in having the thing if we can’t do that. But before that...”
I looked away from the tablet and called out to Hiiragi-san, who was fidgeting while she watched the perimeter.
“Good work, Hiiragi-san. Let’s swap sentry duty.”
“...Okay.”
Hearing my request for the long-awaited swap, she nodded obediently. She looked like she was trying to maintain her composure, but I could tell she was excited.
Yeah. Even though we needed a sentry in the dungeon, I had clearly made her wait too long.
“Okay Yuji, I’m switching out. I’ll leave the rest to you.”
“Got it.”
After giving Yuji the heads-up, I took over the perimeter watch. Hiiragi-san practically hurried over to him, peering at the tablet screen from the side with eyes full of curiosity.
Guided by Yuji’s hands, the drone flew off toward the stairs leading down to the 31st floor.
Despite our fears of anti-air traps or monster attacks, the survey of the 30th floor proceeded without a hitch. Yuji seemed to have gotten the hang of it; his initial stiffness was gone, and the drone zipped through the air near the ceiling with impressive speed.
...That looks like fun. I’m definitely going to practice later.
“Whoops, the battery’s getting low...”
“Already? But it hasn’t even been fifteen minutes, has it?”
“The display says about twenty percent remaining, but that’s just a rough estimate. It’d be a disaster if the power suddenly cut out and it crashed. It’s better to be safe and bring it back with some margin.”
“...I suppose you’re right.”
“Besides, we’ve surveyed most of the area. The drone’s job here is done.”
After convincing a slightly disappointed Hiiragi-san, Yuji began the return flight. Soon, the high-pitched whine of the rotors drew closer. The drone returned without a scratch, proving the scouting run had been a complete success.
“Landing now.”
As Yuji spoke, the drone descended slowly from the ceiling. I watched his face, thinking that a safe landing must be the hardest part, but Yuji didn't look tense at all.
Feeling a bit concerned, I spoke up.
“Yuji, you sure you can land it okay?”
“Yeah. This thing has an auto-landing feature. It’s designed to handle takeoffs and landings with just one button.”
“Huh, fancy.”
As if to prove my worries were unnecessary, the drone touched down perfectly in front of him and the propellers cut out.
Man, drones really are easy to fly these days, despite all the regulations.
“Phew... Alright, that went well.”
“Good job, Hirose-kun. For your first time flying in a dungeon, the footage was excellent.”
“...Thanks, Hiiragi-san. Now then, let’s review what we’ve got.”
Yuji pulled the memory card from the drone and inserted it into the slot on the tablet connected to the transmitter.
“I hope this works... Okay, there we go.”
“Is this... the recording from the flight?”
“Yeah. We were moving pretty fast, so we might have missed something. It’s better to give it a second look.”
Yuji was right. Even watching from the side, the drone had been zipping around. With the narrow field of view on the camera, there were bound to be details we’d overlooked during the live feed.
That said, Hiiragi-san, I want to see the footage too. I think it’s about time we swapped back...
It took about thirty minutes to finish reviewing the scout footage. In the end, Hiiragi-san and I never swapped sentry roles again... well, whatever.
Feeling a little sulky, I listened to Yuji’s summary of the findings.
“The conclusion is that there aren't any notable monsters on this floor besides Grass Lizards—assuming there aren't any tiny ones that can hide perfectly in the grass, anyway.”
“What are the chances of small ones lurking?”
“Probably low. We walked around quite a bit last time we were here, and we only ever ran into Grass Lizards. I don't know about the deeper floors, but I doubt there are any here. We should still stay alert, though.”
“I see...”
“Well, we can’t spot traps just by looking at the footage, so we’ll still be relying on Daiki’s skills for that.”
“I’ve got that covered.”
Overall, the reconnaissance was a success. Since we now had a general idea of where the monsters were lurking, we could calculate a safe route—or at least one with a low encounter rate. As individual enemies, Grass Lizards weren't a major threat, but fighting them took up time and slowed us down. Since we wanted to make as much progress as possible during the summer break, we preferred to avoid unnecessary combat.
Thus, serving as a field test, we headed for the 31st floor using the low-encounter route we’d mapped out.
“Alright Daiki, put the drone away. We can’t exactly carry it around like this.”
“I can do that... but is it okay to store it as it is?”
“Yeah, we’ll be using it again on the next floor anyway. We’ll fold it up or disassemble it before we head home... oh, right. Daiki, when you pull it out next time, give me the spare battery too. The one in there is low, so I’ll need to swap it.”
“Understood.”
I took the drone kit from Yuji and tucked it into my Spatial Storage. The testing was still ongoing, but it looked like the drone was going to be a huge asset. This should keep our progress from stalling out.
I let out a small sigh of relief and finished our preparations to move.
As we actually traveled the route with fewer Grass Lizards, I could feel them lurking nearby, but we almost never encountered them directly. It helped that the Grass Lizards preferred to stay still and wait for an ambush; as long as we didn't wander right into their personal space, they didn't bother to attack.
If they had been the type of monster to actively hunt, we would have been in several fights by now.
“...Alright, we’re here.”
Even though the route was a bit of a detour, we reached the stairs to the 31st floor much faster than if we’d taken the direct route and been swarmed by monsters. We had moved slowly and cautiously for the sake of the test, yet it had taken less than thirty minutes.
If we kept this up, we could probably shave even more time off our travel, depending on the monster types.
“Yeah. Even if it’s limited to these grassland floors, drone scouting is definitely viable.”
“I agree. The movement went almost exactly as we predicted. Since we're dealing with moving monsters rather than static traps, we'll have to scout and verify the route every time, but...”
“It’s still a massive win. Just knowing where the goal is and the general enemy layout makes it an effective time-saving measure.”
There was still room for improvement, but the whole process—scouting, verification, and movement—had taken less than an hour. The drone test was a resounding success. Once we got the hang of it, we might be able to reach the next floor in just thirty minutes, even in new territory.
Well, provided this grassland field filled with Grass Lizards continued.
“Anyway, let's call it a success and head down. We're ahead of schedule, but we don't have forever before we have to head back. If we play our cards right, we might even start on some brand-new floors.”
“True. If we keep up this pace, we can finish the survey of the known floors with time to spare.”
“I’d love to do that. It would be a waste to just survey the known floors when we’ve come all this way for an overnight trip.”
The other two checked the time and agreed that new floor exploration was within our reach. After all, summer break is shorter than it looks, and as students, we didn’t get many chances for overnight dungeon dives. If we could map out the fastest routes to the new floors now, we’d be able to dive much deeper even on future day trips.
To that end, we were all eager to push into new territory.
“Agreed. Let’s head down.”
“Yeah.”
“Let’s go.”
With our goals set, we descended the stairs to the 31st floor.
Once we were on the 31st and 32nd floors, we experimented with different techniques to speed up the drone scouting. We eventually concluded that the most efficient way was to fly the drone in a spiral from the outer edges toward the center to get a complete map of the floor, then retrieve the data and verify enemy distribution. Of course, that only worked as long as there were no anti-air attacks or traps.
By the time we hit the 32nd floor, we had the scouting and verification down to about fifteen minutes. The 31st floor in particular had been a breeze because the stairs happened to be close to our starting point; the whole process, including travel, took only thirty minutes.
“It’s going so well it’s almost scary. You’ve gotten a lot faster at this, Yuji.”
“I suppose. It’s not so bad once you get used to flying at this speed. Though I did clip the ceiling a few times and nearly lost it.”
“The important thing is that you didn’t drop it. Thanks to that, we’ve got plenty of time to start exploring the new floor.”
Like Hiiragi-san said, there had been a few heart-stopping moments when the drone bumped into the ceiling, but the propeller guards had saved us. If it had crashed, we would have had to trek all the way to the crash site to recover it, which would have cost us a huge amount of time. The fact that he didn’t drop it was proof enough of his skill.
“From here on out, it’s brand-new territory. We don’t know what's waiting for us, so let’s be even more careful than before. There might even be enemies that can shoot things down.”
“Right. It’s about time for new monster types to show up. Just because it’s been easy so far doesn't mean it’ll stay that way. We need to stay sharp.”
Yuji, who had been a bit giddy from the drone's success, slapped his cheeks with both hands to refocus.
And then...
“Alright, we still have plenty of time before our deadline. Let’s go.”
“Yeah.”
“Yes, let’s.”
Steeling our resolve, we began our descent toward the 33rd floor.