Having just returned from New El, Goose shared several reports.
"Battalf and Date are already completely deserted. I only stayed for a short time, but there wasn't a single sign of human presence. The same goes for Naminte, of course."
"I see..."
Jin briefly wondered how things would change once the Shouro Empire's investigation team moved in.
Most likely, development would proceed in cooperation with Mitsuho and Fusou Island.
"Or perhaps a new nation will arise."
Goose correctly grasped the intent behind Jin's muttered words.
"Indeed. The old New El may have fallen, but a new New El might be founded in its place."
"True. Though that's still a long way off."
"Before that happens, we need to make Adriana Tierra more widely known to the public..."
Jin felt that doing so was his duty as the Magi Craft Meister.
"There really is a mountain of things to do."
As Jin let out a sigh, Goose retorted:
"Isn't that better than having nothing to do and being bored out of your mind?"
"Fair point. As the saying goes, 'Idle hands are the devil's workshop.'"
"...What was that again? Feels like I've heard it a long time ago."
"Ah, it means that when ordinary... or rather, petty people have too much time on their hands, they never get up to any good."
"Was that it?...Well, I suppose that makes sense..."
As they chatted, a report came in from Laojun.
"My Lord, do you have a moment?"
"Is that you, Laojun? Go ahead. Did something happen?"
"Yes. Regarding the quartz plug in Toka Village, there has been some progress."
"Hmm? Let me hear it....Ah, I'll head over to the laboratory now."
With that, Jin made his way to the laboratory. Today, Mini Reiko was lying flat on her stomach atop his head rather than perched on his shoulder.
"Allow me to deliver the report properly now."
"Go ahead."
First, a map was projected onto the magi-screen. Centered around Toka Village, it encompassed Kaina Village, the Great Shama Marshland, Lake Manuse, and even the royal capital, Alban.
"This is a map of the eastern part of the Klein Kingdom. I will now overlay the underground water veins onto it."
"Right....Ohh."
"I will not display all of them, as that would make the screen overly cluttered."
Even so, a web-like network of underground water veins appeared.
Beneath Kaina Village, rain and snow that had fallen over the great northern mountain range seemed to flow as hidden groundwater.
Part of it flowed into the Great Shama Marshland, while another part ran beneath Toka Village.
"Please focus your attention on the underground water vein beneath Toka Village."
"Got it."
"One of the water veins running toward Toka Village via Kaina Village vanishes just before reaching the Town of Charles. Lacking a water supply and surrounded by an extensive permeable layer, it is believed to have lost its defined channel."
"I see."
The prominent water vein had disappeared not because the water had dried up, but because it had permeated across a wide area.
"So, what about this water vein?"
"Yes, My Lord. It appears someone used the water veins to distribute poison."
"Poison?!"
"Yes. While the mastermind was likely a member of the Magic Federation, this remains speculation as no definitive records survive."
Even so, since this took place around 150 years ago, all the perpetrators were no longer of this world, making it impossible to hold them accountable regardless.
"Back then... or rather, even now, mapping water veins accurately is exceptionally difficult. It is presumed they acted merely on a whim."
The poison dispersal procedure Laojun explained through deductive reasoning was simple.
They threw poison into key wells and waited for it to be carried away by the flow.
Any water veins that gushed forth as springs were sealed completely to prevent the presence of the poison from being discovered beforehand.
"So that's why they blocked the gushing spring in Toka Village before it reached Kaina Village... Good grief."
What a foolish thing to do, Jin thought, unable to suppress a wry smile at the sheer ignorance of the Magic Federation's leadership back then.
After all, Toka Village's hot spring drew water from a depth far below the water veins supplying the nearby wells and surface springs.
If it didn't, the geothermal heat would never have turned it into a hot spring in the first place.
"Just as you say, they likely lacked the capability to investigate the depth of the water veins at the time."
Unable to even properly cast Grand Search, Jin pitied the people of that era.
"I thought it was common sense that you can't master power without knowledge."
"Indeed. The Magic Federation openly proclaimed that as long as one could wield magic, scientific knowledge was unnecessary. It is presumed such foolish schemes were carried out without Markitus's knowledge."
Laojun was rather scathing as well.
"So, what became of the poison? Did anyone get hurt?"
"I examined the records, but found no incident resembling one. It likely diluted far below a lethal dose, resulting in no actual harm."
"...Fools."
"I agree."
Jin and Laojun—or rather,
"They truly are idiots, aren't they..."
All three of them, including Mini Reiko atop Jin's head, were utterly dumbfounded.
"To add to that, we have confirmed at least six source springs that were plugged with quartz. All of them were artesian wells or springs."
"And?...I have a feeling I know how it turned out."
"Yes, My Lord. Sealing the outlet halted the flow from that specific point, but water merely bubbled up nearby, meaning the water sources were never rendered unusable."
"Figures."
In the case of Toka Village's hot spring, Jin's thorough digging and reinforcement of the spring channel had ironically backfired—once plugged, the water had nowhere else to escape and simply stopped flowing altogether.
"I did build it quite sturdily, after all."
Jin realized that, going forward, he ought to incorporate spillways or safety-valve-like structures in case water channels became blocked.
"Yeah, no matter how old you get, there's always something new to learn....Right, do you know what kind of poison it was?"
Jin was curious about what poison the Magic Federation had used.
"Yes, My Lord. Since very few records remain, this is a conjecture pieced together from fragmented information, but it was likely aconitine."
"The wolfsbane toxin, right?"
Most of this knowledge came from the medical texts left behind by Magus Shuuki Tsetse, who had been a medical student.
"Yes, precisely. However, aconitine is almost insoluble in water, so it is presumed to have either settled at the bottom without dispersing or simply been washed away."
In any case, no records of poisoning symptoms or related incidents remained.
"Understood. That settles that matter."
Jin decided that since it was an event of the past and entirely resolved, there was no point in probing further.
"More importantly, let's focus on the future."
"Understood."
After telling Laojun that, Jin asked:
"How is the bus we leased to the Klein Kingdom doing?"
He was curious about the reception of his creation.
"Yes. According to reports from Driver 1 and Assist 1, it is enjoying a very favorable reputation. Though, its full-scale operation is still some time away."
That was only natural, as its primary purpose was to transport tourists for the air race.
"Still, they're running it on a trial basis, right?"
"Yes. They likely judged that jumping straight into full operation carried too much risk."
"Well, that makes sense."
No matter how excellent the bus's performance or ride comfort might be, the Klein Kingdom was the one operating it. If their planning or customer service were poor, it would defeat the purpose.
And so, Laojun explained that they appeared to be testing it as a short-distance transit option.