The leaders of the mercenary guild had fled to the southeast, but why was that?
　When I mentioned the question, Char told me this.

'Five thousand years ago, there was an underground city on the southeast coast. ...... executives may have been headed there.

　Would an underground city mean a place like the ancient ruins of Onen?
　The executives were using an item from an ancient civilization called a 'portable magic terminal', and it's possible that they took it out of that underground city.

　This looks like it would be a good idea to check out the underground city once.
　Maybe we can find out something about the background of the incident.


　However, looking at the clock, it was already 7pm.
　It's already 7pm and I'll have to wait until tomorrow to investigate the ancient city.











　I'd like to say ......, but I take it back.
　Let's go to the underground city today.
　It might be a hassle, but you should definitely go there.

　I've been involved in a lot of flare-ups in black companies, and there's one lesson I've taken to heart.
　It's to "finish the last claws of the case.

　If you don't bother with the final nail, you will almost certainly end up in big trouble later on.
　It is not unusual for a case to catch fire again after it has been extinguished.

　I have a bad feeling about this case, don't you think?
　Our sense of smell, honed by the hellish days in a black company, is alerting us to the danger.
　Don't let your guard down, the case isn't over yet with .......

　And my "bad feeling" is so true that I'm sick of it.

　With that in mind, the investigation of the ancient city should be done exactly today.

　Maybe there's a mastermind behind the mercenary guild, and that guy might be hiding in the underground city.


　* * *


　Examine the underground city by the sea.
　When I told him that, Char looked puzzled for a moment.

''Uh, is it now?''
Yeah. The sooner these things happen, the better.
...... I understand. Hmmm, Kou-sama is an impatient person, isn't he? I'm jealous of your youthfulness.

　I'm sure you'll be able to find a way to make the most out of your time with this one.

...... It's true that Ko is impatient,
I know. I know, I know.

　Iris and Lily nodded deeply together.
　Their gestures were very similar to those of their sisters, which was kind of funny.

''But when Ko makes a sudden move, you're almost certainly ahead of the trouble.
Ko-san, do you have any precognitive skills, or do you have any?
No, I don't have one.

　I shook my head in response to Lily's question.

'In my experience, I'm sensitive to any hint of trouble.
...... Ko, what kind of a mess you've been in, what kind of a mess you've been in?
I don't know.

　I could go on and on about the darker side of black business here, but I'm not going to do it because it's going to depress my mood.
　That was then, and this is now.
　Let's switch it up.

Anyway, we'll get a quick dinner and then we'll be on our way. Is that all right with all three of you?
Of course, Your Majesty. Whenever and wherever you want me to, I'll be there for you, Master Koh.
I'll be fine. Shall we get some food?
There's a bakery across the street from the inn, sir.

　I look out the window.
　The sun has already set, but the bakery across the street from the inn seems to still be open.
　Okay, let's go there.

　The bakery is quite old and seems to be in the 80th year of its existence in the royal capital.
　Our recommendation is the beef cutlet sandwich, which has been the same taste since the establishment.
　The thick beef cutlet, soaked in a special sweet and spicy sauce, has a lot of crunchy texture, and the taste spreads on your tongue with every bite.
　It was so good that I couldn't stop eating it and finished two servings in the blink of an eye.

　...... I'm glad we bought an extra loaf.

　By the way, Char was holding five or six cream buns, and she was devouring them with a happy expression on her face.
　Apparently, he has quite a sweet tooth.

　Iris and Lily bought a variety of breads, and both of them passed half of them over.
　They really are good friends, aren't they?

　After about 30 minutes of eating, Charu spread out a map on the table and explained the location of the underground city.

''The underground city itself is on the southeast coast, but the entrance and exit are a bit further inland.

　That said, I pointed to a place called 'Sides Cave'.
　As for the location, it was a short distance east of Fife's inn town (where they caught the mercenary guild leaders), and it was in the forest that spread out there.

''Hey Char, wait a minute.''

　It was Iris who voiced her doubts.

'I've explored the Sides Caverns solo before, but there were no underground cities anywhere, just low-ranked demons wandering around.
Iris, there's actually a hidden passage in that cave.
Really?!
'Yes. It's hidden in a special way, so you wouldn't normally recognize it.
Does Char understand?
Of course. Leave it to me.

　Charu stretched his chest a bit dependably.
　Anyway, since we found the entrance to the underground city, let's leave.

　I activated 【Spatial Leap】.
　The surrounding landscape is distorted and I warp to Fife's inn town.
Since 【Spatial Leap】can only designate places I've been to before, I should be able to head to the Sides Cave on foot from here.

　I take Iris, Lily, and Charu with me and walk down the main street of the town.

　The time was around 8pm, and the light from the magic lanterns lit up the city.
　All of the taverns facing the main street were packed, and every once in a while a cheerful laugh echoed with a wahahahahahaha.
　Maybe we can go out for a quick drink after we're done exploring the underground city.

　While I was thinking about this, we reached the city gates.
　At the gate of the city, there are several guards and the captain of the guard.
　They are discussing with a very serious look on their faces, but what is going on?

　As I was tilting my head, the chief of the guards noticed us and rushed over to us in a panic.

''Oh!　Isn't that the Dragonslayer?　If you've come to support me as soon as possible!
Backup?

　What on earth is he talking about?
　After listening to the details, it seems that just half an hour ago, there were multiple reports that "demons are overflowing from the East Sidos Cave".
　Currently, several guards are on their way to check it out, but if an outbreak of demons is occurring, it's a big deal, so they've also contacted the royal capital using communication magic tools.

''I received a reply from the royal capital that they would send backup immediately. That's why I thought that 《Dragon Slayer》dono was here: ......
'No, maybe the support would come separately. I'm just here on personal business.

　Well, I was just going to go to the Sides Cave.
　I don't think it's a coincidence that the demon outbreak is happening at this time.
　I guess this case is not over yet, after all.

　...... Next to my thinking about this, Iris and Charu were whispering something to each other in a whisper.

It's just as I said, Char, right?　There's almost certainly something going on when Coe makes a sudden move.
'Yes, ....... To be honest, I'm surprised.

　Char let out a sigh of admiration and continued on with his words.

''If someone like Master Ko had been around 5,000 years ago, maybe our civilization wouldn't have been destroyed. ......

　No, that would indeed be an overestimate.
　I have all sorts of substandard skills, but apart from that, I'm just a human being.
　I don't think I'd be able to fulfill such a grand mission to save or protect the world.

　The only thing I can do is to deal with the trouble at hand as soon as possible.

　
　* * *


　Soon after, the guards, who had been heading to the Sides Cave, returned.
　The guards were in a great hurry and were sweating like a waterfall all over their bodies.

''Ta-oh my God!　That's an octopus!　Buckets like octopuses are flooding out of the cave and heading for this city!

　Char gasped when she heard those words.

'...... No way.'
What's going on?

　When I asked, Char answered with a pale face.

''It was 5000 years ago, but in the ...... underground city deep in the Sides Cave, there was research on magical creatures. The plan was to artificially create demons to fight the plagues.
So, a creature like an octopus...
'They are magical creatures from an ancient civilization. ...... Perhaps someone has reactivated the underground city's facilities.

　So you're saying that this situation was artificially caused, right?
　I don't know who the culprit is, but it might be related to the mercenary guild's case, and we should get into the underground city quickly.