I listened to Yuji’s heroic tales with genuine admiration, and once his report was finished, Hiiragi-san began her own update on the Obon period. In her case, she had mostly been helping out at her family’s shop, so she said there wasn't anything particularly remarkable to report.
Or rather, nothing remarkable for her.
"Heh, so you added a new item to the menu."
"Yes. Apparently, super-spicy food is a trend lately, so I figured we should have at least one dish for it."
"Super-spicy, huh? What kind of dish is it?"
"It’s simple. We just mix a homemade spicy oil into the ramen we usually serve."
Wait, what? That certainly sounded simple, but could you really call that a new menu item? I’d expected something like a new soup base or special toppings.
As I tilted my head and pondered the simplicity of it, Hiiragi-san gave a wry smile and revealed the secret.
"It’s only natural for you to have doubts, Kokonoe-kun. You're wondering if such a simple method really warrants being called a new menu item, right? Don't worry, it actually takes quite a bit of effort. Other shops won't be able to imitate it for a while."
"I see... Is it okay if I ask what makes it so difficult?"
Usually, the seasonings that define the flavor of a signature dish are trade secrets. Even if we were on good terms, I wasn't sure she’d share that information. People are especially protective when it comes to new products.
However...
"I don't mind telling you. The preparation itself isn't much different from regular spicy oil."
"Wait, are you sure? I'm the one who asked, but isn't that supposed to be a secret?"
"It’s a secret in a way, but there’s no problem. The oil used for the flavoring is special."
"Special oil?"
What kind of special oil? Was it an expensive import? While I puzzled over it, Yuji seemed to realize something. His eyes widened slightly in surprise.
"Could it be... is that oil made from the grass that grows around the 30th floor of the dungeon?"
"Correct, Hirose-kun. I'm extracting and refining oil from that grass to use as the base for the spicy oil."
"Ah! That special oil is from that grass!?"
Hearing their exchange, I struck my palm with my fist as the realization hit me. Come to think of it, that grass was extremely flammable because it contained so much oil. Hiiragi-san had brought some of the harvested grass back with her, and while I’d wondered what she intended to do with it, I never imagined this.
True, if you pressed that grass, you could probably extract a decent amount of oil.
"When I checked with the Dungeon Association, they told me the oil from that grass is harmless to humans and perfectly edible. While I was thinking about how to use it, I happened to see a segment on TV about making spicy oil, so I gave it a try. And well..."
"It worked out?"
"Yes. I refined the oil using the same method used for essential oils and added chili peppers. Normally, it takes a month for the flavors to fully infuse, but with this, it was finished in just one hour."
Come again? Something that usually takes a month was finished in an hour? That’s more than just a shortcut... how is that even possible?
"It seems the oil extracted from that grass has a property that allows it to absorb aromatic and spicy components incredibly fast. Thanks to that, I could extract all the heat and fragrance in a very short time."
"I had no idea it had those properties... I thought it was just good for burning as a substitute for alcohol."
"Even if I refined all the grass I brought back, I couldn't even get a hundred grams of oil out of it. If you wanted to use it for fuel, you'd have to bring back tons of grass to make it viable. Diving deep into the dungeon just to lug back tons of grass isn't worth the effort."
Hiiragi-san was right; hauling tons of grass back just for fuel definitely wasn't worth the trouble. There might be a way to refine it into oil before bringing it back, but carrying refining equipment down to the 30th floor... that was currently impossible on floors that only top-class explorer teams could reach. Besides, using fire in an area surrounded by highly flammable grass was out of the question.
As Hiiragi-san said, even if the recipe got out, no other shop would be able to replicate it for the foreseeable future.
"That’s true... Anyway, besides saving time, are there any other benefits to using that grass oil?"
"Yes. I compared it to spicy oil made with regular cooking oil, and the flavor and heat were on a completely different level. Moreover, just one drop makes the ramen sufficiently spicy without altering the base flavor, so the cost per bowl isn't much higher than regular ramen. Well, assuming I don't get too picky about the chili peppers and harvest the grass myself."
So, Hiiragi-san’s material gathering would remain a part of our dungeon exploration for a while longer. Unlike the orcs from before, this grass was easy to collect along our route, so I didn't mind.
Still, in the current explorer market, even "just grass" was a high-end luxury item if it came from those depths.
"The cost would definitely skyrocket if you had to buy it from someone else."
"Plus, as things stand, there are hardly any explorers who can even reach the floors where that grass grows..."
"Exactly. So, sorry to ask this of you two, but next time we dive, could you give me a little time to gather grass? Once summer vacation is over, we won't be able to go that deep for a while, so I want to stockpile as much as possible."
Hiiragi-san bowed her head to Yuji and me, requesting time for her harvest. Yuji and I shared a glance and gave her a light nod.
"Yeah, that’s fine with me."
"Me too. It's on the way, so it shouldn't take long."
"Thank you, both of you. I'll treat you to our shop's new ramen later."
The new ramen... she meant the super-spicy one. I’m really not good with spicy food... but well, it’ll be a good story, so I’ll accept the treat. Yuji, on the other hand, looked perfectly fine with it—he actually seemed excited.
Once the report meeting for the Obon period was finished, we moved on to discussing our next expedition. Summer vacation was entering its final stretch, which meant our time for multi-day dives was running out.
I wanted to push our dive depth as far as possible, since our next chance for a long trip wouldn't be until winter vacation.
"So, departure the day after tomorrow?"
"Yeah. Tomorrow would be fine too, but it’s better to have a day for final preparations."
"Right. I want to restock some of the preserved food I've used up, too."
The date was set without any friction, so the conversation moved to our target floor.
"We reached the 34th floor last time, so I think we might be able to aim for the 40th floor."
"True. If the terrain isn't too difficult and the enemies aren't a nightmare, the 40th floor is a realistic goal..."
"But the 40th floor is ten levels away from the 30th floor where we've been setting up our base camp. If we're going to set up a new camp near the 40th floor, I'm a bit worried about whether we'll have enough time to properly secure the perimeter."
"Hmm..."
Based on our past pace, I figured we could reach the vicinity of the 40th floor within our schedule, but as Hiiragi-san pointed out, it was unclear if we could find a safe spot for a base camp. Until now, we’d relied on the 30th floor—a place with great visibility that we knew well, allowing us to secure a clear retreat to the upper floors.
"In that case, I'll go check for floor information at the Association before we leave. I don't know how much they've made public, but even if it costs a fee, it’s better than going in blind."
"Good idea. Knowing what kind of monsters to expect would be a huge help."
I didn't know how much detail they would have, but even basic information about the monsters or the general environment of those floors would be a win. Ultimately, we’d still have to verify everything ourselves once we were down there.
Still, getting a lead on which floors were suitable for a base camp would be invaluable. Floors infested with small, fast monsters were much harder to pull sentry duty on than those with large ones.
"I'll head to the Association tomorrow while I'm out for supplies."
"Do you want me to come with you, Daiki?"
"No, I’m just asking for info. I can handle it. Though if the data is expensive, I’d appreciate it if we could split the bill."
"Of course. We're splitting the info, so we should split the cost. Right, Hiiragi-san?"
"Yes, definitely. It’s only fair."
And so, I decided to visit the Association the next day. While information on the shallow floors is widely available, once you get past the 30th floor, I wasn't sure if there would be any data at all. Groups like the Self-Defense Forces or the police teams might have reached those depths, but if they had, floor movement restrictions might be in place—limiting the information to government-affiliated explorers.
Still, it was worth a shot.
"Thanks. I'll let you know what I find."
"I'm counting on you, Daiki."
"Please do, Kokonoe-kun."
After settling the plans for the day after tomorrow, Yuji and Hiiragi-san headed home. Once they were gone, I called Mika and Saori-chan into my room.
It was time to tell them about the relaxation of the old floor movement restrictions and the new rules we’d just decided on.
"Ahem. Well then, I'm going to announce the results of your recent test... I mean, the exploration."
"Eh!? Wait, does that mean you're easing the restrictions!?"
"Hold on, calm down."
The two of them, who had looked curious when I called them in, suddenly turned frantic with anticipation as soon as they realized what I was talking about. I felt bad for making them wait, but they needed to settle down first.
Once I got them to sit back in their seats, I delivered the verdict.
"The conclusion is that you passed. After discussing it with the others, we've decided that you’re allowed to dive as deep as the 10th floor."
"...!? We did it!"
Hearing the word "pass," Mika and Saori-chan threw their hands up in the air and cheered. Seeing them so happy made me feel even more guilty for having dragged the announcement out.
If the Obon holiday hadn't interrupted us, I could have told them sooner.
"...That said, it doesn't mean you can just dive to the 10th floor whenever you want, okay?"
"Wait, what?"
"Humanoid monsters—goblins—start appearing from the 7th floor."
Both of them stiffened. Their expressions of joy vanished, replaced by a momentary twitch of unease as their eyes wavered.
"I know you both have experience killing goblins. But there are countless explorers who find themselves unable to strike a humanoid monster and end up seriously injured. Being able to cross that line is a major borderline that determines whether you can actually keep being an explorer."
"..."
"So, I want the two of you to spend some time on the 7th floor getting used to fighting goblins. Start with one at a time, then move up to two, and so on."
Mika and Saori-chan looked at each other, searching for a reaction. They were likely recalling the time they had fought goblins during a previous dive. After a long moment of silence, they both nodded and turned back to me.
"I understand. We'll do what you and the others say and focus on getting used to the 7th floor for a while, Onii-chan."
"Thinking back to before, you're right. It would be dangerous to suddenly jump to the 10th floor," Saori-chan added.
The look in their eyes had changed. They looked determined.
Yeah, with that attitude, they should be fine once they gain a little more experience.
"I'm glad you understand. For the record, it took us quite a while to get used to killing goblins, too. It’s not something you master in two or three encounters. Don't rush it. Pushing yourself too hard is how you get hurt... and you're lucky if it's just an injury."
"Okay."
"We understand."
It seemed they were properly convinced. I’d been worried they might insist that goblin hunting would be a piece of cake. In terms of pure strength, they were more than a match for goblins, but the mental aspect was a different story.
I understood their desire to keep up with the people around them, but I didn't want them to get hurt because of a reckless impulse. After all, I’d seen a prime example of that kind of recklessness quite recently.
"All right, that’s all from me. Just remember, don't overdo it in the dungeon. Be cautious."
"I know, Onii-chan. If I get hurt, I'll just make Mom and Dad worry."
"I'll be careful too."
They looked at me with expressions meant to reassure me, and I responded with a look of my own, telling them I was trusting them.
Now that the news was delivered, I could focus on our own dive starting the day after tomorrow.