After Lin Heng left, Qianzhou came to the room to look for the letter left by Professor Finn according to his instructions. Xie Qingfeng followed behind him without saying a word, and the tears in the corners of his eyes had been wiped clean.

"There's no need for you to keep getting involved. Qianzhou kindly dissuaded, "Go back and sleep." ”

Xie Qingfeng smiled gently, and his tone was soft but resolute: "Whether there is a need or not is not up to you." ”

Qianzhou was silent.

He heard the desistence in the girl's words, and dealing with this situation was exactly what he was not good at.

While the two were talking, An Zhe had already found the letter: "This letter is addressed to you. ”

Qianzhou took the letter——

My dear student Qianzhou,

It must be the grace of Mother Earth that allows me to meet you in this last year.

I am amazed by your attainments in arithmetic, and in some respects you have surpassed me. What's even more rare is that you can always come up with new ideas, unlike an old man like me, who is already thinking about the future.

"I don't have any attainments, I'm just picking up people's teeth. ”

Qianzhou laughed at himself and continued to read-

I am very happy every time I discuss arithmetic with you, but unfortunately my body is not getting worse day by day. Perhaps it won't be long before I return to the arms of the Mother Goddess. As you can see, I have no wife and no children. Although I don't know why you are alone in Yundu, if these things outside my body are useful to you, please feel free to take them.

"Do you still care about me at this time?"

There's another thing I don't know if I should say or not, and it's a secret that our family has decided to keep without permission. Even I don't know if it's true or not, but it can only be said that it was my grandfather's whim. If you're interested, solve the puzzle below, which is also my childlike innocence.

At the end of the letter are several multiple integrals and a composite function.

Qianzhou himself didn't notice that at this moment, he actually started mental arithmetic directly without the help of paper and pen. The answer to a few questions about the time it takes to breathe has already been found. Then bring in the function and sketch the coordinate system in your mind.

When the difficulties were solved one by one, what came to Qianzhou's mind was a symbol similar to the "8" that had been put down.

"Ouroboros?"

"No, it's not. When it comes to mathematics, it's supposed to be 'infinite'. Qianzhou's heart suddenly brightened.

In other words, Professor Finn hid the secret in something related to infinity. Then Professor Finn's home must have a clue I missed!

Chishu put the letter in his pocket and ran out despite the surprised gazes of the other two.

Seeing this, Xie Qingfeng immediately chased him out.

An Zhe also wanted to follow, but he suddenly stopped as if he had received some instructions, took out a jade plaque from his pocket, and his face was stunned: "Xuanxing Pavilion's Grade A document, [Natural Disaster Su'e] has appeared in the 100,000 Great Mountain? Wait, why is the signal gone!"

At the same time, the Xuanxing Pavilion, the ruling organ of the Qin State's transcendent organization, began to operate at full capacity. Documents were signed here, and orders began to be sent in an orderly manner.

The first to set off was the Dragon Horse, and with the help of the dragon vein, they could reach any place in the Qin Kingdom within an hour.

After that, the scholars of the Hanlin Academy also hurried to the 100,000 Mountains to jointly revise the rules and lay out the Great Wall.

Then a red-covered document arrived at the Heavenly Pavilion, and the sealed artifact began to be activated......

In addition to these extraordinary institutions, various administrative agencies also have their own functions - the assessment and classification of hazards, the evacuation of civilians, the transportation of baggage......

The machine named "Qin" began to run at full capacity, and after 80 years, it was ready to compete with the "natural disaster" again!

In the Xuanxing Pavilion, a gray-haired old man lit a cigarette after signing the last document and leaned back in a chair quietly.

"Ahem. The old man coughed lightly.

Seeing this, the girl standing behind the old man couldn't help but ask worriedly, "Teacher, are you okay?"

The old man shook his head: "Xiao Si, the Qin State has been founded for more than a thousand years, and it has faced natural disasters no less than 100 times, and the most critical one has five natural disasters within the border at the same time. But the Qin State has always stood tall, relying on the unity of the whole country, and the public is private first, you should remember this. ”

The girl nodded.

After a pause, the old man said, "Every time we deal with a natural disaster, no matter how well we are prepared, there will be heavy casualties. If this is a script, then the author is too cruel. ”

Everything that happened is still a little far away from Qianzhou for the time being. Qianzhou rushed to the street and stopped a carriage casually. Xie Qingfeng followed in.

The girl held the carriage with one hand, gasping slightly, her cheeks were red, a layer of fine beads of sweat hung on her forehead, and a few strands of green silk from her sideburns were stained on her face. Even in this way, the girl is not embarrassed, but has a sickly beauty that holds her heart.

"Why bother. Qianzhou was a little unbearable. He knew that if the girl continued to follow up like this, sooner or later she would face a deeper darkness.

Xie Qingfeng laughed: "Then why do you bother? How long have you known Professor Finn? Brother Heng has been my brother for ten years." ”

"Can't it be counted like this?" Qian Zhou shook his head, "You also saw that Lin Heng and An Zhe are not ordinary people. Otherworlds exist. ”

The girl did not reply, her eyes were stubborn and bright, as bright as sparks.

As if stung by this burning gaze, Qianzhou turned his head and sighed helplessly: "Okay, but you must know that this road is not a smooth road, I hope you can walk with energy." ”

After that, the two of them who were restless did not speak, and silently let the carriage pass through the streets and alleys of Yundu. At night, the various light sources on the side of the street cast dappled shadows through the windows, making this warm and indifferent, bustling but deserted city more and more blurred.

The carriage went very fast, and in a short time it reached its destination.

Qianzhou took Xie Qingfeng through the cold courtyard and entered the house. The incandescent light in the room had been around for a few years, and the light was slightly dim.

I don't know if it was because I was in a hurry last time or because of some other reason, Qianzhou felt as if he noticed more details.

In the living room is a wine cabinet with several bottles of wine, one of which is only a third of the way down.

Qianzhou knew that Professor Finn didn't like to drink, and that most of the wine came from Professor Finn's students and friends.

The soul sublimation seemed to improve Chishu's memory, and if he remembered correctly, the bottle should have been full when he came at noon on October 15th.

Qianzhou opened the wine cabinet and took out the wine to look at it carefully.

This bottle is made from the Buller region, and the material is a fruit called purple peach, which is quite high. It is clear from Professor Finn's letter that he is a believer in Mother Earth Goddess, and in the teachings of Mother Earth Goddess, this wine symbolizes friendship.

Qianzhou pursed his lips, he had always been dismissive of religion and gods.

Don't look at the teachings of the major churches now, they are much more tolerant, but if it was a thousand years ago, when human wisdom was not opened and theocracy was at its peak, they launched a religious trial without mercy, and I don't know how many innocent people were burned at the stake.

The major churches have been preaching to the Qin state for more than 100 years, but the results are not ideal, and only some churches have been established that are more like attractions.

"Is there anything wrong with this wine?" Xie Qingfeng asked curiously.

"No, no. Qianzhou carefully put the wine back in the wine cabinet, then solemnly closed the door, and then walked straight to the study.

The study is still the same messy appearance. Qianzhou walked to the bookshelf and soon found a book in the corner called "The Application of Infinity in Arithmetic", written by Professor Finn.

Qianzhou took out the book, pinched the cover, and knew it.

He carefully removed the cover of the book, and sure enough, he found dense handwriting on the back. At this moment, the key to solving most of the mysteries was held by Qianzhou.

After reading the words on the cover, combining the information he received from Aurora with the settings he had written, Chishu gradually sketched a picture that spanned a thousand years.