Toa Eschenbach, the head of House Eschenbach, was an alchemist. His daughter, Saki Eschenbach, was something of an apprentice in the same field.
Alchemy was once defined as the study of transmuting base metals, such as lead, into precious metals like gold. From a broader perspective, it was the art of discerning the essence of matter to create entirely new substances.
However, as the eras passed, the discipline evolved. In the modern day, it had become a branch of academia essentially equivalent to chemistry. While there were still those who obsessed over transmuting gold or creating a homunculus, the mainstream had shifted toward more practical chemical pursuits. The primary difference between this field and the chemistry of modern Earth lay in the intervention of magic.
"Saki-sama, it is time for your meal."
Lawton, a servant of House Eschenbach, called out from the hallway.
"……"
He received no reply. Steeling his resolve, Lawton opened the door to the workshop.
"…!"
He recoiled at the acrid stench that hit him.
In the center of the workshop, a pile of yellow powder sat atop an iron plate over a burning fire. Saki was slumped on the floor beside it.
"Saki-sama!"
Lawton held his breath and dove into the room. He scooped Saki up, rushed back out into the hallway, and slammed the door shut.
"Haa... haa... haa..."
Saki’s breathing was ragged, but she seemed to have remained conscious. Lawton watched over her for several minutes. Once he saw her breathing return to normal, he turned on her with a voice sharp with reproach.
"Saki-sama! What on earth were you doing?!"
Had he arrived a moment later, she might have died.
"A-Ah... sorry, Lawton. I was just... curious about how flower petals decolorize when held in the smoke of burning sulfur. It was so fascinating that I simply lost track of everything else."
The decolorization was the result of the reducing action of sulfur dioxide gas. However, sulfur dioxide was highly toxic. If inhaled, the poisonous gas could lead to death by making pulmonary respiration impossible.
The workshop, now presumably filled with toxic fumes, could not be used again until the windows were broken and the room was ventilated for two full days.
"Hey there, Esse! I've got something rare for you!"
A farmer carrying a bucket knocked on the door. "Esse" was the common abbreviation for House Eschenbach used by everyone in the neighborhood.
"Hmm? What is it?"
Saki peeked out from behind the door. The farmer set the bucket down in front of her.
"Found these in the lake. Strange little stones, aren't they?"
Inside the bucket were several nearly transparent stones, each shaped like a slightly skewed rectangular prism.
"No matter how much you break 'em down, they always end up in this same shape."
"Ho... how fascinating. I'll buy them."
Saki reached into her pocket and haphazardly produced three silver coins. The farmer accepted them with a delighted grin and went on his way, leaving the bucket behind.
"Hmm, let's see. If I crack it like this... Oh! It really does break into the exact same shape! How marvelous."
Saki absentmindedly set one of the small, cleaved stones down on an open book. The volume was the General Theory of Alchemy, written by her father, Toa Eschenbach.
Though he had written it primarily to supplement the family's income, the book had become a bestseller in the world of alchemy. Occasional royalties flowed into House Eschenbach as a result, which was where the silver coins in Saki’s pocket had come from.
Regardless, as Saki looked at the stone on the page, she nearly leaped out of her chair in shock. Through the transparent stone, the text beneath it appeared doubled.
"Th-This?! Could it be that this stone has the power to multiply objects?!"
For the next twenty-four hours, Saki threw herself into researching the stones, forgetting both food and sleep. Ultimately, she learned nothing of substance and eventually collapsed facedown on her workbench in exhaustion.
"Milady!"
Galt, another servant, came rushing into the room and hurriedly helped Saki up.
"Ugh... so sleepy... hungry... I want to eat something..."
Galt let out a long, weary sigh.
"Please decide whether you want to sleep or eat first..."
"My name is Lona. I look forward to serving you."
The girl who gave a polite bow was seventeen or eighteen years old. She was the newest servant hired by House Eschenbach.
"I'm Saki. Nice to meet you, Lona."
Saki had previously only dealt with male servants, so she felt more at ease with a girl around and tried to be considerate... at first. Eventually, things returned to their usual state.
"Saki-sama, please wake up! It is almost noon!"
"Mnn... just a little longer... I was up until dawn..."
Staying up late and sleeping until noon was the best-case scenario.
"Saki-sama! Have you still not eaten?!"
"A-Ah, sorry. I was just... the properties of this stone were so interesting."
"What are you saying?! I left lunch right beside you! And now it's already night!"
There were times when Saki would become so absorbed in her research that she forgot to eat entirely.
"Lona, I'm sorry. It seems we're out of money this month..."
"Hah... again? This makes two months in a row without wages."
"I'm truly sorry. We should have funds coming in next month."
As Saki apologized, Lona watched her with an increasingly troubled expression.
"Hmm, hmm. I wonder if this liquid could be used as a coating?"
In a bucket sat a black, viscous liquid. A traveling merchant, hearing rumors that House Eschenbach had a weakness for rare things, had brought it to them, claiming it was a special tree sap.
Saki scooped a bit up with a spatula and spread it onto a board. Despite its thickness, it spread into a remarkably thin layer. This suggested that even a small amount could cover a vast surface area.
"I imagine this could be quite efficient."
Saki had high hopes, but the black sap showed no signs of drying the next day, or even the day after. When she poked it with a finger, it remained tacky and pulled away in thin threads.
During one of these checks, Saki accidentally scratched her cheek with her sticky finger. She hurriedly wiped it off with a cloth, but by that night, her face had begun to itch intensely.
"Ugh, it's so itchy. What's happening?"
When she couldn't take it anymore and scratched, the itch would subside for a moment, only to return even stronger. The cycle repeated until she found it impossible to sleep.
"Milady, it is morn—!!"
Lona, coming in to wake Saki, gasped in horror. The right side of Saki’s face was horribly swollen and covered in blisters. Blood seeped from the places she had scratched, creating a truly gruesome sight.
"Ky-Kyaaaah!"
Lona couldn't help but scream. She couldn't be blamed for her reaction.
"Ah, that feels better..."
Saki applied a wet towel Lona had prepared, the coolness numbing the itch slightly. However, Lona refused to come anywhere near her. Seeing the swelling on Saki’s face, the girl was convinced it was some sort of contagious disease.
Then, Lona voiced her resignation.
"Thank you for everything."
"Wait, Lona, won't you reconsider?"
"No. Even if you ask, I've reached my limit. Saki-sama, please take care of yourself. Give my regards to the Master."
Lona gave a deep bow and left without a single backward glance.
"...Good grief. Was she the third one? Or the fourth? It really is a bother that the servants won't stay put..."
This occurred exactly three days before Ar was completed.