East side of the pinning.
　I walked out of the gate, enduring the heat for about half an hour.
　I could see the forest ahead of me.

　The forest looks more like the south forest than the north forest in Laffan, and it seems to be more or less inhabited.

　In front of the forest, there was a simple fence.

　It was quite poor, about waist high. It was quite old and some parts were rotten and crumbling.

　It is useful in the sense that it marks the boundary, but as a fence, it is completely useless.

It looks like the land in question from here. There's a fence.
I can usually get over it.

　Yuki said as she jumped over the fence.

"Me too!　Me too! Me too!
Me, me!

　Mitya follows Yuki and jumps over, followed by Mary.

　The fence is a little high for Mitya, but he can easily jump over it, so he is very athletic.

　The rest of us also climbed over the fence and entered the forest.

This entire forest is the private property of the brewery. ....... It's pretty big.

"Including the mountain behind it, to be exact. And it's not private land, it's land that's been granted exclusive use.

　It seems that the land itself is owned by Viscount Nenus, and the brewery in question has only been issued a permit by him.

　But that, on the contrary, seems to be a factor that makes people hesitant to enter.

　Needless to say, the psychological hurdle between breaking into a private home of a commoner and breaking into the home of a nobleman is naturally higher in the latter case.

　In a place like this, there would be no one to blame, but without our entry permit, we could not legally complain even if we were suddenly beaten to a pulp.

　Most people wouldn't think of going in.

Phew, it's pretty cool. In the woods.
"Yes. It's like bathing in the forest.

　Once we entered the forest, the surrounding temperature became noticeably cooler.

　The tall trees blocked the sunlight, and as we walked through them, a cool breeze blew through from time to time.

　As a matter of course, the locations of the roads marked on the map were well maintained, and the rest of the area did not look dense.

This looks like it could be used as a tourist spot.
"Yes. It looks like a well-maintained hiking trail.
Not if you consider the purpose.

　Originally, this forest and its hinterland were protected in order to obtain good water.

　The forest and its hinterland were originally protected to obtain good water. I don't know what they're doing to maintain it.

　Even the path we are walking on was built to carry water, not to be a walking path.

　From my point of view, it seems wasteful to set aside so much land just to get water, but this is a world where there is a surplus of land. But in this world where there is a surplus of land, there is not much of a problem in that respect.

　However, the cost of maintenance is also putting pressure on the brewery's finances, as it requires manpower.

　How could they be so particular?

"Anyway, if we walk down this road, we can get to the water intake ...... pond, right?

"According to the map, yes. It's a little bit uphill. ...... Shall we walk there?

It's been a while since I've had this kind of leisure time.

　In the event that you've got a lot of time to spare, you'll be able to take advantage of it.

　Of course, I've been keeping an eye out with my [enemy search], but so far there has been no reaction from the demons.

　It may seem strange, but this is normal.

　It seems that the area around Raffan is unique, and there are actually fewer demons in the forest.

　However, it seems that one out of every three forests is inhabited by demons, and there are dangerous creatures like Weipu Bear even if they are classified as animals, so it's hard to say that most forests are safe.

"Well, we're only half playing today. Just take your time and walk around.
"Yes!

　Mary and Mitya replied happily, looking around as they walked.

　For these two, who have almost no experience of going out of town, it must be an interesting experience to be able to walk leisurely through the forest.

　Following them, we walked along the path leading from the forest to the mountain.

　　　　We walked along the path from the forest to the mountain.

　About an hour's walk from the foot of the mountain, we came to a mortar-shaped hole, about 200 meters in diameter.

　Looking down from the edge of the hole, we saw a pond with a diameter of about 30 meters at the bottom, and the water was a deep shining blue.

　The water was very transparent and clear, but still so deep that I could not see the bottom clearly.

...... beautiful.

　I'm not sure what to say, but I'm going to say it.

　It's a good idea to have a good idea of what you're looking for.

　It seems to me that there's something wrong with the water, but since they've been using it to make ale for so long, it's probably not a problem.

　It looks really bad, though, with its sapphire blue color.

"Wow!　It's a beautiful blue!
"It's so blue!

　Mitya and Mary are running down the path that leads to the pond.

　Toya followed them on foot.

　If it was in the forest, I would have rushed to stop them, but there is no response to the [search enemy], the vegetation in the mortar is slightly different, the trees are sparse, and the visibility is good.

　If you fall down, you might get hurt, but there is no need to worry about demons or anything like that.

This hole could possibly be a crater?

　You'll be able to find a lot more than just a few of them.



It looks like the mountainside was blown away by the eruption. Like the Hōei crater on Mt.

Though on a much smaller scale.

Wouldn't that mean that the pond is a volcanic crater with water gushing out of it?

Do you think that's possible?　I don't know much about geology, but...

　I don't know much about geology, but..." Haruka answered my question while twisting her neck.
　I don't know much about geology either, but I do know that lakes can form in craters.

But if you think of it as volcanic, the blue color makes a little more sense.

Is that so?

Yeah. Water without microorganisms can become that color. It happens on Earth, too.　But that's because it's hotter. ......

That looks like normal water, doesn't it?

At least it's not steamy.

　Other causes, such as high acidity or high alkalinity, might make the water uninhabitable for organisms or plants and clean (only in appearance), but I don't think you can use such water to make ale.

　On the other hand, if the water is poisoned with something we don't understand, that would be even worse.

"Let's just go down there. We're here to investigate.

Right.

　The four of us followed Toya and the others down to the side of the pond, where Mary and Mitya were playing in the water, with Toya standing behind them watching.

　Seeing them together, we relaxed a little.

It's a good thing we brought her, isn't it?
"Yeah.

　Mary hadn't shown any signs of crying since she met us, but her expression was often stiff.

　It was only natural.
　She had suddenly lost her father, who was her protector, and was left alone with her sister, whom she was supposed to protect.

　No matter how much we said we would protect her, her anxiety would not disappear.

　But after spending time with us for the past few days, she seems to have forgiven us a little, and her expression has become a little softer, and she is smiling happily more often today.

"Hahaha, it's cold!　It feels so good!
"Nao-san, the water is really cold!

　It's a little cooler in the forest, but it's still summer.
　It's still hot as usual.

　I crouched down by the pond and put my hand in the water, it was so cold that it made me sweat.

It's cold!　But it feels good.
It's blue!
It's blue, but it's not blue!

　The water is blue, but it's not blue!" Mitya curiously nodded his head as he scooped the water into his hands.

The water is not colored.
Is that so?
Really?" "Yes. The reason why it looks blue is .......

　The water looks blue from above, so the question is understandable.

　We also wonder why it looks so blue.

　In principle, we understand that it is due to light, but to explain it, we have to go to .......

"Natsuki, pass.

　I'm sure you'll be able to figure out what's going on.

　I'm not sure if it's a good idea, but it's a good idea.

I can explain.　I can explain it to you, but it takes a lot of scientific knowledge to understand it. ......

　There are certainly many things that need to be explained, such as the principle of color vision, the wavelength of light, and the absorption of light.

　There are certainly many things to be explained, such as the principle of color vision, wavelength of light, and absorption of light, etc. It would be difficult to explain them simply to a child who has no knowledge of such things.

"Well, Mitya-chan. The reason why this pond looks blue is the same reason why the sky looks blue.

Well, let's see... ...... I bet there's a blue ceiling all the way up high!

　In a way, it's a very childish answer.
　In a way, this is a very childish answer. Since it looks blue, it is natural to assume that there is something blue.

A ceiling. Not exactly. The air and water here are actually a very pale blue color. When many, many of them gather, they become darker.　So you could say that the air that is gathered in large numbers is the 'blue ceiling'.

"Oh, really?　It's amazing!

　Mitya sounded surprised at Natsuki's explanation, and Mary nodded in admiration as she listened.

　I'm not sure what to say, but I'm going to try to explain it in a way that's easy to understand. .......

I'm not sure if that's a good idea.

I'm sure you'll be able to figure out what's going on.

(Ordinary colors are reflected, so the principle is a little different from diffusion, but it's hard to explain to children.

(There's also sunset, so it's not exactly the same thing. ......)

"Haruka, Yuki, if you have a better explanation, I'm all ears.

　I'm not sure if you can hear our private conversation, but Natsuki said this with a nice smile, but Haruka was silent for a moment and then quickly changed the subject.

Now, let's investigate the pond.

　I'm sure Haruka can explain exactly what she means, but it's a bit difficult to explain it to a child, especially when you have to break it down so that a child in this world can understand it.

　At the very least, I can understand that it is not something that can be explained in a short time.

　And there's nothing I can say, since I passed the explanation to Natsuki.

Huh. ....... Mitya, Mary. Strictly speaking, my explanation is a little different, but it's very difficult to explain exactly. If you really want to know exactly what's going on, study hard. If you really want to know exactly what it is, study hard, and you may find out.



Really?　Hang in there.

"I understand.

　Mitya and Mary nodded obediently to the precautionary line that Natsuki had put up, but I wondered if they would be able to understand it through the studies of this world.

　I'm a little curious about that, but if it leads to a desire to learn, then I guess it's possible.

　No matter, I'm now investigating the pond.

"It's quite a strange pond, isn't it?

　When I looked into the pond again, I found that it was so deep that it plunged down sharply from the shore, and I could not see the bottom.

　Even so, the transparency is high, and we can see at least 20 meters deep, which is quite deep.

　Because of its high transparency, you feel as if you are looking into an empty hole rather than looking into a pond, and the deep blue color gives you a sense of fear that you might be sucked in.

　Of course, I know that it's no different from swimming in a place where you can't get your feet on the ground. .......

I'm not sure what to make of this. It looks like.

　Yuki, a little dumbfounded, scoops up the water, spills it, and looks at the clear, sparkling water.

It's fine to touch. I don't have a problem touching it, and I don't know if it tastes ...... good.

　I squat down, scoop out some of the pond water, and take a sip.
　It's very cold and tasty, what's wrong with that?

Nao, are you okay?

I'm sure you'll be fine. If it gets bad, Haruka, please?

We'll fix you up, but what about ...... Toya?

Let's see. ...... Hmm, maybe a slight bad smell, huh?

　I also drank some water, and then tilted my head slightly and said, "I'm not sure.
　I took another drink of water and ...... couldn't tell at all.

I can only detect it with my sense of smell.

...... In other words, the craftsmen at the brewery felt it, right?

That's right. --He's a really good craftsman. But not as a manager.

　It's hard to imagine that his sense of smell is as good as Toya the beast's, and his sense of taste is ridiculously sharp. ......?

　No, it's not impossible that the craftsman is a beast.

So let's say the smell is the problem. What could be the cause?

　I looked around, but I didn't see anything obvious.

　It would have been better if there had been some obvious trash on the ground. But, of course, there was none.

"This is probably spring water, right?

　Nodding at my words, Yuki pointed to a corner of the pond.

There's also a river, but it's too small to sustain this pond.

　There's only one river that flows into this pond, and it's too small to be called a stream.
　There is also no river flowing out of the pond.

The outlet for the water would have to be inside the pond.
Volcanic land has a lot of gaps.

　If the water is supplied and discharged by the cavity created by the volcanic activity, it is possible that the water is so clear even without rivers?

　But then, .......

If the cause is the spring water, there's nothing we can do about it, right?
Yes, it is. At least we're not talking about the water this year.

　Haruka agreed with Toya who said in a dumbfounded tone.
　Haruka agrees with Toya. Mary hears her words and asks curiously, "Really?

"Is that so?

"Yeah. Water from a spring is water that has been gushing out for several years, decades, or even a hundred years. So even if we find out the cause now, it will be a long time before the problem is corrected.

"Oh my God!

　I was relieved to see Mitya raise his hands in surprise, but if that was in fact the cause, then it was serious.

　If it was caused decades ago, it would be difficult for us to find the cause, let alone solve it.