Professor Holmes is not a villain.

The meeting with Miss Holmes was a disaster (7)

“I was going to write ‘Rachael,’ but due to unavoidable circumstances, it seems it wasn’t completed. Perhaps, given the slightly altered spelling, the culprit might be someone with a relatively lower level of education or someone who speaks in a dialect.”

“And?”

“That’s what the stupid Scotland Yard officers will think. Actually, I can guarantee that most of them won’t even reach the part I just added. Or they might not even think it has any significance in the first place.”

At the girl’s response, Moriarty smiled with satisfaction. Sherlock, feeling happy to see her teacher smiling at her, also smiled innocently.

However, the deduction wasn’t over yet. The answer hadn’t been found. That’s why, as an educator, Moriarty asked again.

Without pressuring or scolding, but with the conviction that she, at the very least, could figure out most of the answer, he asked again.

“Well then, continue. What do you think it means?”

For a moment, the girl’s expression darkened. There was a mix of frustration in her face. Yet, the brilliant girl seemed to realize why this extraordinary teacher had presented her with such a riddle.

Moriarty became even more fond of this interesting girl.

“It definitely has another meaning. So… this must be what you call intuition, right?”

Since her teacher nodded instead of answering, Sherlock let out a small sigh and continued speaking. Of course, that sigh was directed at herself.

It was filled with frustration at her inability to provide an answer despite having uncovered most of the clues to the riddle.

“But… I don’t know. As frustrating as it is, within the limits of my knowledge, I can’t figure out exactly what RACHE means. Perhaps it’s a foreign word, right? You gave me this riddle to emphasize the importance of accumulating various kinds of knowledge.”

“Yes, you’re right, Sherlock. It seems you’ve grasped my point well. You are a clever child, aren’t you?”

Sherlock had to force herself to suppress the corners of her mouth from lifting at the compliment, which wasn’t quite a compliment. It was indeed a strange feeling.

Of course, she knew full well that this teacher before her was truly an exceptional adult. But the feeling she got from receiving praise from him was different from when her mother or father praised her. It was a sensation she had never experienced before, and it left her slightly bewildered.

The girl was, after all, human. No matter how brilliant or smarter than adults she might be, and even if she could sometimes see what others could not, she couldn’t help but feel good when praised.

Being praised by her parents, of course, felt nice. She loved her family. Even though they were sometimes ordinary, boring, or failed to understand her, she genuinely loved them.

Therefore, receiving praise from them was naturally a pleasant thing.

But at the same time, it was also an entirely expected thing. The girl took pride in her intellect. She knew she was extraordinarily smart, so being praised felt like the most natural thing in the world.

Was that why?

The praise she received from the man before her—the man she acknowledged—felt special, as though it was genuine recognition for achieving something remarkable.

Of course, Sherlock didn’t forget to ask about the answer to the riddle.

“So, what does RACHE mean, teacher?”

“Revenge.”

Moriarty uttered the word briefly. It was a term that might sound somewhat grim, but Sherlock nodded and accepted it simply.

“I see, so that’s it. ‘Revenge’ in a foreign language… That’s certainly intriguing. So, what language does it mean ‘revenge’ in?”

“German.”

“In that case, it might be the work of anarchists that people often talk about. Or it could be the work of someone trying to disguise it as such.”

“….Do you even know what kind of people anarchists are when you say that?”

Even though Moriarty acknowledged the girl’s intelligence, the word she uttered was unexpected, prompting him to unknowingly ask again.

Sherlock shrugged lightly.

“I don’t know exactly. Anyway, I learned they’re bad people. Specifically, from serialized novels.”

“Well, to some extent, opinions might vary depending on political and social perspectives. But what’s important is that you need to learn who such people are to draw your conclusions. The same goes for the German language. So, how do you feel after solving the riddle, Sherlock?”

“…I can certainly understand what you meant, teacher. If I had known German, I could have solved it perfectly.”

“As you can see, accumulating knowledge is important. It also helps, to some extent, in developing intuition. Intuition is like a sense, but the broader your range of knowledge, the more it helps to cultivate it. If you hadn’t suspected it might be a foreign language, would you have even attempted to solve this riddle?”

The girl didn’t answer immediately. But as if determined to firmly follow her teacher’s teachings, she stared intently at Moriarty, almost to the point of being overwhelming.

Of course, Moriarty didn’t feel burdened by her gaze. Others might have.

In fact, if a pretty child stared like that, anyone would naturally feel her gaze. A few years down the road, when the girl reached Moriarty’s current age, any man might find himself blushing and looking away first.

But Moriarty only smiled faintly. Even he couldn’t yet determine why he was doing this.

However, teaching and guiding Sherlock, this bright girl, was undoubtedly an enjoyable task. The lesson continued.

“Of course, I won’t teach you math all year long, but most would agree that math can be somewhat helpful in developing intuition. So, I’ll teach you a few basic principles, Sherlock.”

“Alright. If you say so, teacher, I should naturally follow.”

Although the girl was already halfway trusting and following Moriarty, the riddle earlier had solidified her resolve to trust and follow the man in front of her.

Now, without any protest, the girl’s eyes sparkled as she focused on Moriarty.

Where should he begin?

Moriarty pondered briefly. There was no need for a systematic lesson. After all, Mrs. Holmes wouldn’t expect such a thing, so he only needed to teach what was necessary.

Thus, Moriarty decided to start freely. Both Moriarty and Sherlock enjoyed freedom, so there were no complaints.

There were undoubtedly many differences between the man and the girl, but there were even more commonalities. Perhaps it was a fateful connection.

Of course, neither Moriarty nor Sherlock believed in such things. At least, the two of them didn’t.

But the lessons had to continue. Moriarty finally spoke.

Just as with himself and Sherlock, he began by introducing the most special concept in mathematics.

“Well then, I suppose we should start with prime numbers. I heard this is your first time learning under a private tutor, but you know basic arithmetic, don’t you?”

“I’m not a child, teacher. I can do much more complex calculations. By the way, prime numbers? What are those?”

Moriarty smiled at her childlike curiosity.

“They are special numbers in many ways. Mathematicians who study math professionally are always obsessed with and fascinated by them. They’re unique and extraordinary numbers that can only be divided by 1 and themselves.”

Of course, there were more complex and alternative definitions academically, but there was no need to explain those to a young child.

The girl was clearly not destined to become a mathematician. Moriarty only needed to use math as a tool to impart appropriate knowledge and guide her.

“Only divisible by 1 and themselves… That’s special. It’s like being a unique person, with only one other who can truly understand them besides themselves.”

For a moment, the girl fixed her gaze on Moriarty without even realizing it. Unfortunately, Moriarty couldn’t fully grasp the reason behind her childlike thoughts. If he had known what was going on in her young mind, he might have acted a little differently.

But unaware of this, Moriarty continued speaking.

“I thought you’d focus on that aspect. There’s a lot of fascinating work you can do with these prime numbers, but you’ll learn about it gradually. The important thing to note is that these prime numbers are infinite.”

“How do you know that?”

It was a question typical of Sherlock. Moriarty, without realizing it, affectionately patted her head. Her inquisitive attitude was admirable, and this small being, who brought him so much joy with every action, felt endearing.

Of course, Moriarty immediately realized he had acted impulsively by patting her head. It was a rare moment for him—emotional actions were almost unheard of for him.

Sherlock felt similarly. If it had been anyone else, even her mother, she would have protested and refused. She always considered herself an adult and detested being treated like a child.

Moreover, the two had known each other for less than three days, no matter how special they found one another. Yet, Sherlock didn’t reject Moriarty’s touch.

When Moriarty withdrew his hand, she felt a twinge of disappointment without realizing it. To ease the awkward atmosphere and return to the original purpose, Moriarty resumed his lecture.

“That was proven by our great Euclid using a method called reductio ad absurdum. Ah, of course, you’ll learn about reductio ad absurdum eventually. I think you’ll enjoy it very much. But not yet. For now, just remember that they are infinite.”

“Alright. So, what’s next?”

“The problem is that prime numbers are rather erratic and lack any apparent pattern. Mathematicians around the world are still working hard to find one, but for now, there isn’t any. That’s why we rely on a challenging process to identify these special prime numbers.”

Moriarty calmly wrote down the numbers from 1 to 50 in a prepared notebook. Sherlock, focusing intently, didn’t make a sound, watching his every move.

When he finished preparing, Moriarty spoke again.

“This might even relate to a method you enjoy. Long ago, there lived a man named Eratosthenes in ancient Greece, Sherlock. He devised a method. It seems simple, but it remains unique to this day, and detectives you admire always use this method.”

“What method is that?”

“It’s simple—eliminating them one by one. First, you remove 1. Since 1 doesn’t belong to any group, it isn’t a prime number. Next is 2, the first prime number and a very special one. Naturally, multiples of 2 aren’t prime numbers. You understand up to this point, right? So, what should you do?”

“You should eliminate all multiples of 2.”

Following Sherlock’s words, Moriarty began crossing out every multiple of 2 up to 50, excluding 2 itself.

The clever child already understood what her teacher was doing.

“Ah, I see. You’re finding and eliminating clues one by one.”

“Exactly. Then comes 3. Since 3 is also a prime number, you remove all its multiples. Next is 5, then 7, and so on. What do you think? Isn’t it intriguing?”

The girl nodded absentmindedly as if entranced by his explanation.

Her heart began to race. Though she had already sensed it, Sherlock felt certain that the upcoming year would be incredibly enjoyable and fulfilling.