Assuming the monsters couldn’t swim, I suggested we make a stand with the reservoir at our backs. She rejected the idea outright.

“If we charge into a cave blindly, we could be surrounded.”

I tried to hint at what had happened when we died in the cave earlier, but she didn’t change her mind.

“Putting the water at our backs only takes away one direction they can surround us from. It might make us even easier to trap, and even if we retreat into the water, they’ll catch us eventually.”

I looked over the reservoir again. It sat in the middle of the underground chamber, with no visible outlet and no wall close to it on any side. She was right. Swimming didn’t look like a good way to escape the monsters.

I scratched my head. The military tactics I’d heard about in my previous life weren’t much use in a real fight. No, the tactics weren’t the problem. I just didn’t understand them properly. I’d picked up bits and pieces from novels and online posts. I’d never fought a battle or studied tactics seriously, so of course my suggestion was no good.

“Still, what you said about being surrounded in the cave—and the possibility that the monsters can’t swim—is worth keeping in mind.”

She took my suggestions and came up with a new plan, one far more convincing than my idea of making a stand with the water behind us.

‘Who is she, really? This isn’t the sort of plan an ordinary mercenary would come up with.’

Thinking that, I followed her. Interestingly, she entered the same cave we’d taken before we died. I could have suggested another, but I followed without a word. There was no reason to switch caves and risk some unexpected obstacle, like a dead end.

We had killed the monsters and were walking through the same cave. So far, events were unfolding just as they had before my death. This time, though, we moved differently. We walked at half our former pace and stopped at regular intervals to listen in every direction. Both of us were several times more cautious.

RUSTLE.

Before long, I heard something. I pressed a mana-enhanced ear to the wall and could just make it out: the monsters’ footsteps. They stayed distant for a while, then fell silent once they drew closer.

“Are the monsters really following us in secret?”

She had heard them too, and looked at me.

“Seems that way. I bet others are waiting up ahead.”

She stared into the darkness ahead. “Probably. Good grief. They’re herding us, aren’t they? Were these things always this smart?”

After muttering her complaint, she looked back at me. “It’s remarkable. How did you know? To be honest, I could hardly believe you until just now...”

I knew because I’d been through it, but I couldn’t tell her that. “I have good instincts.”

“Instincts... So you’re not just clever.”

Judging by her expression, I had a feeling there would be a new rumor about me besides the one calling me a genius—if we got out of here.

“Well, shall we follow the plan?”

“Yes.”

We turned around and ran back the way we had come. I poured mana into my legs. The cave sped past, and from behind us—no, from ahead of us now—I heard hurried footsteps.

SCRABBLE, SCRITCH.

Before long, we spotted the monsters that had been following us. Being surrounded from both ends of a straight cave like this would be dangerous, but only once the trap had closed. Until then, each part of it was ours to take down separately.

“We have to finish them quickly!”

“Don’t worry!”

As she charged ahead, the tip of her sword shimmered. The sword in my hand began to glow faintly too. Four monsters approached, filling the cave. That was one more than we had fought earlier, but fewer of them could reach us at once. They were so large that only two could stand side by side, and the ceiling was too low for those behind to leap over them. We each had only one monster to face.

I drove mana into my legs and hands and thrust my sword with all my strength.

“Dodge this if you can!”

The cave was too narrow to swing my huge sword freely, but it was even harder for the monster to evade. Hemmed in by the other monsters, the walls, and the ceiling, it could barely move, let alone use its usual speed. I held my sword out and slammed forward with my whole body.

THUNK.

The blade pierced the foreleg raised to block it, then drove through the ratlike monster’s head.

“Grrrk.”

As I’d thought, fancy swordplay was unnecessary in a cave like this. I kicked the monster off my blade and rushed forward again. The next one went down quickly too.

As expected, the Firebird Hunter defeated her monsters faster than I did. Even so, she looked impressed as she watched me bring mine down.

“Are you really ten? How can you be that skilled at your age?”

“It’s thanks to my ability.”

“An inherited ability that produces knight-level or greater abilities at ten?”

Damn. Had I shown too much? But hiding my strength would have made it hard to survive. Fortunately, she left it at that.

GRRRR.

The sounds of monsters came from deep within the cave we’d been heading toward. Those were the ones waiting for us.

“Well, what do we do now?”

Perhaps because events had unfolded as I’d predicted, she asked for my opinion. Unlike before, she seemed willing to consider almost anything I suggested. But we already had a plan, and I had no better idea.

“Let’s retreat, as planned. We’ll reduce their numbers as much as we can.”

“Sounds good!”

We hurried back toward the underground chamber where we’d started, the one with the reservoir. As we ran through the cave, we spotted a hole we hadn’t seen before.

“That hole wasn’t there earlier, was it?”

“No. The monsters that followed us must have made it.”

“I knew they could dig tunnels, but can they do it that easily?”

If you don’t know, how would I? Still, I thought I understood how they’d surrounded us so easily. Their sharp claws weren’t for bringing down prey; they were for digging. Was that why they were so hard?

We ran past the hole in the wall and kept going. Fortunately, despite their speed, the monsters didn’t have much stamina. Their sounds came no closer, and we reached the chamber with the reservoir. Then we entered another cave.

We moved in and out of the caves, killing monsters while staying as close to the reservoir chamber as possible. We listened carefully: when a small group approached, we attacked first; when there were too many, we retreated to the chamber and took another cave. Sometimes we misjudged their numbers and found ourselves in danger. Once, we went too deep and nearly got surrounded. In the end, though, we managed to kill most of them.

“So we’re finishing it here after all.”

I said it to her as I sat on the ground, scooping up water from the reservoir to drink. We were back in the underground chamber where we had first landed. Dead monsters lay scattered around us. Once they realized we were using this chamber as our base, they had converged on it. They surrounded us, and we ended up making the very stand with the water at our backs that I’d first suggested.

This time, though, there weren’t many monsters left to surround us. We had cut their numbers drastically by taking them down in smaller groups. Six remained in all—few enough for the two of us to handle now that we were familiar with how they hunted. In the final clash, we brought down every last one.

After drinking, I looked around. “They really did seem reluctant to come near the reservoir, didn’t they?”

“They did. But I don’t think it’s because they can’t swim...”

Tilting her head, she knelt on one knee, cupped water in both hands, and drank cautiously. I watched her for a moment, then turned my gaze to the reservoir. It looked like an ordinary underground reservoir with a hole in the ceiling. Then again, perhaps an underground reservoir full of drinkable water wasn’t ordinary at all.

“There must be a reason, but now isn’t the time to study the monsters’ underground ecology.”

Once my strength returned, I got to my feet. We waited a long while, but no more monsters appeared. It seemed safe to relax. She apparently thought so too. After putting her cloak back on, she asked me a question.

“Shall we go?”

“Yes. Let’s head back.”

We headed for the caves again. “Aren’t those monsters worth some money?”

“They are, but we have no good way to carry them out. And taking them out would cause trouble.”

With no guarantee that the treasure vault was still intact, selling even the monsters seemed like a good way to make some money. Unfortunately, we couldn’t let anyone else know what had happened down here. I would have trouble explaining it to the people at the mansion, and she didn’t want others to learn about the tomb.

‘We’ve killed all the monsters, so the domain should be safe.’

I wasn’t the lord or his heir. There was no need to bring them a problem that didn’t concern me. Suppressing both my disappointment and my lingering worry, I walked on.

From what we’d seen while fighting the monsters, all these caves led upward and joined one another along the way. The chamber where I’d died before was one such junction, and beyond it, fewer and fewer passages continued upward. After climbing for some time, we noticed the cave had changed. This passage hadn’t been dug by monsters. Stone walls and pillars supported its ceiling. It was a man-made underground corridor.

“Could it be... still there?”

At the thought that the secret vault might remain, a spark returned to her eyes. She lifted the lantern from her waist and hurried forward, almost skipping. I followed as best I could, dragging my sword behind me.

Small rooms lined the corridor, but disappointingly, they held nothing except old, broken tables and chairs. We gave them a quick look and kept going until we reached an iron door at the end of the passage. It bore the same pattern engraved on her sword. This had to be the door to the secret vault she sought.

With a trembling hand, she pushed it.

CREEEAK.

Fortunately, it wasn’t locked. The door opened little by little with a harsh scrape.