The sprawling estate of the Prince of Yue sat deep inside the Yankang Ward.
It was prime real estate, yet most days the enormous compound sat completely empty. Its vacant courtyards and still pavilions soaked up the warm winter sunlight, with hardly a servant or guard in sight.
Over in the Xinghua Ward, the situation was entirely different.
The Yan brothers occupied a modest private residence that buzzed with activity from dawn until nightfall. Their days were packed with work, and they went about their routines with the methodical precision of men who had far too many responsibilities and nowhere near enough free time.
Neither household, of course, had any idea that a small disaster was currently rolling toward the western gate of Chang'an.
Li Chunfeng had absolutely no idea what was coming for him either.
A slight rosy flush colored his face, the result of one cup of morning wine too many. He stood just outside the towering western gate, waving goodbye to the friends who had ridden with him all the way from Yong County.
His friends had business in the countryside and could not stay. They waved once, turned their horses around, and headed back down the eastern road.
Li Chunfeng watched them go for a moment, then turned toward the massive stone archway that led into the capital. His small rented house lay somewhere past the West Market, and his legs already felt like they belonged to someone else.
He desperately needed one more night of solid rest.
The 10-day winter holiday was officially drawing to a close. Tomorrow was a workday, which meant the brutal grind of imperial bureaucracy would once again descend upon him. Whatever peace and freedom he had enjoyed during the holiday were about to disappear, replaced by endless reports, calculations, meetings, and the sort of administrative headaches that made a man question every career decision he had ever made.
Li Chunfeng took a deep breath and started toward the gate.
Then he stopped.
Someone had caught his eye.
A young servant boy stood just outside the gates, twisting his neck from side to side as he anxiously searched the crowds.
Li Chunfeng recognized the face immediately.
It was Ruan Yang'er, a young waiter from a particular restaurant in the East Market.
The food there was phenomenal, and Chunfeng considered himself one of the establishment's most loyal customers. He had eaten there often enough that the staff knew his usual dishes, his preferred table, and probably his drinking tolerance better than he did himself.
But what was a restaurant employee from the East Market doing all the way out here at the western gate?
Curious, Li Chunfeng raised a hand.
"Hey, Yang'er! What are you doing out here? Who are you waiting for?"
The young waiter whipped his head around.
Ruan Yang'er had been running between the western gate, the eastern gate, and every inn in between since sunrise. The Chancellor's men had dragged him out of bed before dawn and pressed a scrap of paper into his hand. On it was a rough description of a man's face, along with a very generous payment from the Chancellery office.
He knew Li Chunfeng's face better than anyone. So they had stationed him at the western gate and told him to watch every traveler who came through.
The moment he spotted Li Chunfeng, his anxious expression transformed into absolute ecstasy.
For one brief moment, Chunfeng expected the boy to run over and greet him.
Instead, Yang'er spun around and screamed at the top of his lungs.
"Commander! Over here! That is Li Chunfeng!"
Li Chunfeng froze.
The little warmth in his face suddenly had nothing to do with wine.
Commander?
Why the hell would a military commander be looking for him?
A commander of the imperial guards was a serious figure. His men handled palace security, investigated high-level treason, and dealt with matters that could shake the imperial court. They did not spend their mornings hunting down random civilians who happened to be standing near the western gate.
Li Chunfeng's wine-soaked brain was still struggling to reconcile those facts when the world suddenly tilted sideways.
"Move! Official business! Do not block the road!"
"Soldiers! Clear the way!"
"Go, go, go!"
The roar came from behind him. Before Li Chunfeng could even turn around, a dozen armored men burst through the crowd, moving like a tide of iron and leather. Street vendors hurriedly dragged their carts aside, while parents snatched children out of the soldiers' path.
"What... hey! Hey! What is going on?" Li Chunfeng stumbled backward, both hands raised. "I am nobody! I am a law-abiding citizen! I have done nothing wrong!"
Nobody paid the slightest attention to him.
Two soldiers seized him by the belt and hoisted him clean off his feet.
"Wait, wait, wait, wait!" Li Chunfeng kicked wildly in the air, sending one sandal flying into the crowd and the other skidding across the stones. "Sir, please, do not hit me! I have a grandmother who depends on me!"
The commander grabbed him by the collar and yanked him closer.
"You have a grandmother?"
"Yes! She is eighty years old! She is blind! She is dying!"
The commander stared at him for a moment.
"She died five years ago. I checked your file."
Li Chunfeng's face went pale. Of course she was dead. He knew she was dead. He had attended the funeral. He had stood by the grave in the cold spring rain and watched them lower the coffin into the ground.
But he had panicked and grabbed the first excuse his wine-soaked brain could find.
"You have a file on me?" he managed.
"We have a file on everyone."
Nearby, an old woman selling steamed buns leaned over and picked up the remains of Li Chunfeng's crushed hat. She examined the flattened mess in her hand before looking at the chaos unfolding around her.
"What did that poor man do?" she asked her neighbor.
"It must be treason," the other woman whispered, her eyes wide. "They only grab people like that for treason."
"But he looks like a drunkard. What could he possibly have done?"
"Do not be fooled by appearances, old sister. Traitors come in all shapes."
"I am not a traitor!" Li Chunfeng shouted over the commander's shoulder. "Your sister is a traitor! Your whole family is a traitor!"
The neighbor gasped. The old woman dropped the crushed hat and clutched her chest.
"Did you hear that? He insulted the soldiers!"
"He must be mad!"
Li Chunfeng twisted and kicked, desperately trying to break free, but the soldiers had no intention of letting their prisoner escape. One seized his right leg while another caught the left. Together they flipped him over and dumped him face down across a saddle like a sack of grain.
"Oof!"
The air shot out of his lungs.
The commander swung onto the horse behind him and spurred the beast forward.
"Make way! Make way!"
The horse surged into the street, sending a fruit cart crashing sideways. Apples and pears bounced across the stone road as the merchant stumbled backward, shouting curses at the soldiers.
Then he caught sight of their insignia. He went pale and immediately changed his tone.
"My fruit! My good pears!" he wailed, bowing repeatedly. "Forgive me, forgive me! I said nothing. I said absolutely nothing."
Li Chunfeng lifted his head just enough to see the merchant's terrified face.
"I am sorry about your pears!" he shouted.
"Shut up!" the commander snapped.
"I am just trying to be polite here, sir!"
"You should be thinking about yourself right now, not about someone else's fruit."
"Sir, I think I am going to be sick!"
"Do not."
"I am serious!"
"For the love of heaven, just shut up."
The horse thundered deeper into the West Market, where the crowds grew thicker and hundreds of curious faces turned toward the commotion.
A silk vendor's entire stall collapsed as the horse tore past, sending a waterfall of red and gold fabric spilling across the street. A group of children screamed with delight and chased after the horse like it was part of some festival procession.
"Mama! Mama! Look at the man on the horse!"
"Stay back! Do not touch him! He is probably sick with something!"
"I am not sick!" Li Chunfeng hollered from the saddle. "I am nobody worth noticing!"
At the edge of the crowd, a scholar in a blue robe frowned as he watched the spectacle.
"Did you hear what he said?"
"That he is nobody worth noticing?"
"Then why is half the West Market watching him?"
His companion considered this for a moment before shrugging.
"Maybe he is right. Maybe he is nobody. The soldiers must be having a very slow day."
"In this dynasty? Who can tell."
Li Chunfeng heard every word. His face burned red with humiliation.
"I did not do anything wrong! Nobody will even tell me what is happening!"
His protests only stirred more murmurs among the crowd. A few people laughed, others looked genuinely worried, but most simply stood there with their mouths hanging open as the horse and its loudly protesting cargo disappeared around the corner.
The commander urged the horse into a narrow side street, and for a brief moment, the deafening noise of the West Market faded behind them.
Li Chunfeng tried to catch his breath as the horse carried him onward. His ribs ached, his head pounded, and his hat was gone. One sandal had disappeared somewhere in the West Market. The other was probably halfway to the East Market by now.
Then they reached the main avenue leading toward the Imperial City.
The avenue was packed with people. A diplomatic procession was making its way in from the west, with foreign envoys in unfamiliar robes riding equally unfamiliar horses while officials in formal caps stood in neat rows along the roadside. Commoners crowded behind them, pointing and whispering as they tried to catch a glimpse of the distinguished visitors.
Then, right through the middle of it all, came a lone horse at full gallop with a screaming man draped helplessly across its saddle.
"Make way! Emergency order from the Chancellery!"
The crowd immediately parted, but not before thousands of eyes turned toward Li Chunfeng.
"Is that a criminal?"
"He must be important."
"He looks like he is about to die!"
"I am not about to die! I am perfectly healthy!"
"Then why is your face purple?"
"Because I am upside down! Look at the position!"
The foreign envoys turned their heads as well. One of them, a short man with wide eyes, pointed at Li Chunfeng and said something in a language nobody around him understood.
The translator beside him leaned over and quietly explained.
The envoy nodded slowly before saying something else.
Li Chunfeng lifted his head from the saddle.
"What did he say?"
The translator cleared his throat.
"He said that, in his country, only very important criminals are dragged through the streets like that."
Li Chunfeng wanted to die.
"I am not important! I am nobody! I am the least important person in this entire city!"
The envoy nodded again and said something else.
Li Chunfeng's stomach sank.
"What did he say this time?"
The translator hesitated.
"He said that, in his country, important criminals always say that."
Li Chunfeng closed his eyes.
This was becoming a nightmare.
The horse plunged through the gate, and the roaring noise of the civilian markets finally disappeared behind them. The atmosphere changed almost immediately. The endless shouting of vendors and merchants faded away, replaced by the measured clatter of hooves against polished stone.
Li Chunfeng could hear the commander barking orders somewhere behind him. Gate guards called out as wooden identity tallies were checked and verified. Every sound seemed sharper now that they were inside the heavily guarded heart of the capital.
His dizzy mind slowly began piecing the clues together.
They had crossed the security threshold.
They were inside the Imperial City.
And that realization finally frightened him more than being dragged through the West Market.
This was not unfamiliar territory to Li Chunfeng. In fact, he had spent years working inside this heavily fortified sector of Chang'an.
Long ago, his mentor, Liu Wenjing, had recognized his talent and recommended him for a clerical position attached to the staff of the Prince of Qin.
At the time, Li Chunfeng had been exactly the sort of scholar the military bureaucracy did not know what to do with.
He studied the stars.
He understood celestial movements, calendars, and obscure astronomical texts. He could spend an entire night staring at the sky and happily explain what he thought the heavens were trying to tell them.
Military strategy, however, was another matter entirely.
He had no talent for battlefield formations, no instinct for command, and absolutely no desire to learn how to organize thousands of men into neat lines so they could kill one another more efficiently.
During his time in the prince's camp, Li Chunfeng therefore became remarkably good at being useless.
More importantly, he became remarkably good at being invisible.
Then came the first year of the Wude era.
The political winds shifted, and Liu Wenjing was falsely accused of treason.
The executioners took his head.
After that bloody purge, Li Chunfeng learned a lesson that no book had ever taught him: being noticed by powerful people could be considerably more dangerous than being ignored by them.
So he made himself even more invisible.
He kept his head down, buried himself in old books, and quietly continued his studies. He never volunteered opinions unless someone specifically asked for them, and even then, he usually found a way to make himself sound less interesting than he actually was.
Nobody asked for his advice.
Nobody cared that he existed.
Li Chunfeng preferred it that way. For years, that strategy worked perfectly.
Everything changed after the incident at the Xuanwu Gate.
The Prince of Qin violently seized the crown and became Emperor Li Shimin. Li Chunfeng happily joined the chorus of officials shouting "Long Live the Emperor." He was thrilled that his old boss was now the supreme ruler.
Under the new regime, he finally got a chance to show off his actual skills.
He submitted a brilliant proposal regarding the imperial calendar. The Emperor liked it. Li Chunfeng was promoted to the position of Doctor within the Grand Astrology Bureau.
It was a safe job.
He studied the movements of the stars, corrected the agricultural calendar, and researched obscure mathematical theorems and ancient Daoist texts in total peace.
Until today.
That sudden scream at the city gate had shattered his peaceful existence.
The moment the soldiers grabbed him, his mind flashed straight back to his dead mentor Liu Wenjing. He was absolutely convinced he was being dragged off to the execution blocks.
Listening to the muffled sounds of the Imperial City, however, he realized they were heading toward the administrative offices, not the underground prisons of the Judiciary.
His racing heart finally started to slow down.
He might actually survive the morning.
The horse skidded to a sudden halt.
The intense fear had drained his adrenaline. Li Chunfeng tried to slide off the saddle, but his legs refused to cooperate. His knees turned to jelly.
He hit the ground and immediately began to collapse.
The commander caught him with one hand. The armored man sighed, threw Li Chunfeng over his shoulder, and carried him the rest of the way.
The bright winter sun vanished as they crossed a wooden threshold into a dimly lit administrative chamber.
The commander dumped him into a wooden chair.
Li Chunfeng slumped forward, trying to catch his breath. He heard the commander snap to attention, the sound of metal armor clanking through the room.
"Sir. The target has been secured. Li Chunfeng is here."
A warm, familiar voice answered from across the room.
"You do not need to be so formal, Junxian. You brought him here quickly. Excellent work. You are dismissed to attend to your other duties."
Commander Li Junxian turned and marched out of the room. The heavy wooden doors clicked shut.
Chancellor Fang Xuanling stood behind a huge desk.
He looked at the terrified scholar slumped in the chair, pale and sweating, and let out a sigh of amusement. He walked over to a small charcoal stove and poured a steaming cup of tea with his own hands.
He pressed the hot porcelain cup directly into Li Chunfeng's shaking fingers.
Fang decided to start with some basic small talk.
The young man in front of him was destined to be remembered by future generations as a mathematical genius.
Right now, he just looked like a terrified rabbit. He needed a moment to calm down.
"Doctor Li." Fang Xuanling kept his voice gentle. "Did you travel back to your hometown for the New Year?"
Li Chunfeng shrank back into the wooden chair.
It was a folding chair, completely different from the traditional floor mats he was used to. He felt awkward and exposed.
He took a sip of the scalding tea.
"Yong County, Sir Fang. My family home is only about 100 li from the capital walls. If I rent a decent horse, I can make the journey in half a day."
Fang nodded in understanding.
It made perfect economic sense. A Doctor of the Astrology Bureau earned a microscopic salary. The cost of living in Chang'an during the festival season was astronomical. Rather than freeze in a tiny rented room in the capital, traveling home to celebrate with his parents was the only logical choice for a low-ranking official.
The whole situation was actually Fang Xuanling's fault.
Back on the third day of the new year, the Light Screen had revealed the importance of advanced mathematics. The Emperor immediately summoned Fang Xuanling and Du Ruhui for a secret meeting.
They hammered out a sweeping plan in two days. They were going to establish a brand-new government department called the Mathematics Pavilion.
Drafting the imperial blueprints for the new department was incredibly easy.
Finding the actual geniuses to run it was a nightmare.
The future texts explicitly praised a Tang Dynasty math prodigy named Li Chunfeng. But when Fang Xuanling tried to summon him, the man had vanished from the capital.
The Chancellor grew desperate.
He eventually outsourced the manhunt to the imperial guard, giving Commander Li Junxian a name and telling him to find the genius before the holiday ended.
Fang Xuanling looked at the bewildered scholar who had been legally kidnapped and dragged here by military force.
It was time to pivot to business.
"I have heard some interesting rumors about you, Doctor Li." Fang leaned forward slightly. "They say you are highly skilled at mapping the calendar. But they also say your true brilliance lies in pure mathematics. Is this true?"
The question pulled Li Chunfeng out of his panic.
He blinked, confused by the line of questioning.
"I would not dare call myself brilliant, Sir Fang. I merely possess a solid understanding of the concepts."
"Excellent." Fang Xuanling beamed, flashing a smile that was far too friendly for the situation. "His Majesty has decreed the creation of a new department. The Mathematics Pavilion. And the Emperor has personally ordered your immediate transfer."
Li Chunfeng nodded politely, waiting for the rest.
"You are being promoted to the position of Vice Director." Fang paused for effect. "Congratulations, Li Chunfeng."
Li Chunfeng sat frozen in the chair, holding the hot teacup against his chest.
He blinked once. He blinked twice.
He understood every word the Chancellor said. His brain comprehended the vocabulary. But when he strung those words together, they made absolutely zero sense.
He was doing a perfectly fine job as a Doctor of Astrology. Why was he being transferred?
And what did Fang Xuanling mean by Vice Director?
Vice Director?
Li Chunfeng felt his own eyebrows climb so high he half expected them to disappear into his hairline.
Suddenly, the young man exploded into motion.
Li Chunfeng wanted to throw his hands in the air. He wanted to bow. He wanted to dance. He completely forgot he was sitting in a folding chair instead of kneeling on a floor mat.
He threw his weight forward. His feet tangled in the wooden legs.
Physics took over.
There was a loud crash.
Li Chunfeng went over backward. The chair flipped up into the air. Tea splashed across the floor. The genius of the Tang Dynasty landed flat on his back in a tangle of wooden limbs and spilled water.
Even the pain of hitting the floor could not suppress his excitement.
Vice Director!
That position was second only to the absolute head of a department.
Even though the Mathematics Pavilion was a brand-new creation, the imperial ranking system was clear. The Vice Director of the Directorate of Imperial Manufactories was ranked at Class 4 Lower. The Vice Directors of the Palace Library and the Inner Palace were Class 4 Upper.
What was his current rank as a Doctor in the Astrology Bureau?
Class 9 Lower. He was literally at the absolute lowest rung of the entire imperial ladder.
If he nodded his head right now, his name would echo across the entire capital by tomorrow morning. He was being offered a promotion of 20 consecutive ranks in a single day.
The enormity of imperial favor crashed down on him. This was entirely unprecedented in the history of the Tang Dynasty.
But those exact words suddenly threw a bucket of ice water over his burning excitement.
He cooled down immediately.
Untangling himself from the chair, he stood up. He understood the personality of Emperor Li Shimin very well. The Emperor was not a foolish man. He did not hand out grand rewards on a whim.
Li Chunfeng was not related to the royal family. He was not a wealthy aristocrat like Zhangsun Wuji. He was just a nerd from the provinces.
If the Emperor was dumping this much unprecedented favor on his head, it meant the job came with an equally unprecedented level of terrifying responsibility.
Could he actually survive this job?
Pushing his excitement down, he cleared his throat and looked the Chancellor in the eye.
"Sir Fang. What exactly is the purpose of this Mathematics Pavilion?"
Fang Xuanling did not hesitate. He had rehearsed this pitch for days.
"You will research the mathematical theories of the ancient masters. You will expand the borders of mathematical knowledge for the entire Tang Empire."
The Chancellor raised his hands, painting a picture in the air.
"You will calculate the geometry of the highest heavens. You will measure the vastness of the deepest oceans. You will write a flawless new calendar for the Zhenguan era. You will use the power of numbers to help every single ministry streamline their operations and manage the citizens."
Li Chunfeng listened to this sweeping, majestic poetry.
He processed the insane scope of the mandate.
He had exactly one reaction.
"I am completely unworthy of this monumental task, Sir Fang. Please beg His Majesty to rescind the royal decree."
Whoever wanted a 20-level promotion could have it. Li Chunfeng wanted absolutely nothing to do with it. This job sounded like a one-way ticket to a stress-induced heart attack followed by an execution for failing to measure the ocean.
He bowed deeply, turned around, and marched toward the door.
Fang Xuanling reached out and grabbed him by the sleeve, pulling him back into the center of the room.
The old politician was smiling broadly.
"Sit down, Doctor Li. Do not be so hasty." He guided Li Chunfeng back toward the chair. "If you truly feel you cannot shoulder this specific burden, then tell me something."
He waited until Li Chunfeng was seated again.
"Who can?"
Emperor Li Shimin had given Fang Xuanling absolute authority to build this department.
The Chancellor was a master chess player. He had prepared two completely different strategies for this exact meeting.
If Li Chunfeng had blindly accepted the job, Fang was going to pull out a brutal written exam and test him on the spot. Fang had spent the last year secretly studying advanced math at the Imperial College. His own skills were sharp now. He would not tolerate a fraud.
But Li Chunfeng had declined the top job out of terror.
This triggered Fang's backup plan.
He was going to use this young genius to recruit other geniuses.
Fang knew that Li Chunfeng ran in very strange social circles. As an official of the Court of Imperial Sacrifices, Chunfeng interacted with people from all walks of life. He knew the weird, brilliant misfits who slipped through the cracks of the traditional six ministries.
The request was perfectly reasonable.
Li Chunfeng sat back down. He thought for a moment, then offered a name, one Fang already had on his shortlist.
"If we are talking about raw mathematical ability, Sir Fang, there is only one man for the top job. The Assistant Director of the Astrology Bureau. Wang Xiaotong."
Li Chunfeng spoke the name with absolute reverence. He spent the next five minutes giving a passionate speech about the older man's brilliance.
Fang listened and nodded in total agreement.
Wang Xiaotong was a legend. Back in the Sui Dynasty, his reputation as a math prodigy was unmatched. When Fang was grinding through his own studies, the textbooks he used were all annotated by Wang. The man had taken the ancient, confusing texts of the Nine Chapters and the Continuation of Mathematics and made them readable.
In reality, the Emperor and the Chancellor had already locked Wang Xiaotong in for the Director position.
"Anyone else, Doctor Li?" Fang asked, brush in hand.
Li Chunfeng rattled off a few more names. Fang carefully recorded every single one. Once these men passed a basic competency test, they would be immediately drafted into the new Pavilion.
Fang was not worried about anyone refusing the call.
Talented men like Wang Xiaotong were currently rotting away at Class 7. If they taught at the Imperial College, they might slowly crawl their way up to Class 6. They would never break the invisible barrier to reach Class 5, where the real power lived.
But this new Mathematics Pavilion was the Emperor's personal pet project.
Entry-level teaching jobs started at Class 5 Lower. The pay and prestige crushed anything the Imperial College could offer.
The temptation was irresistible.
Li Chunfeng gave him over a dozen solid names.
Then the young scholar suddenly stopped talking.
He looked uncomfortable, fidgeting in his chair, fighting an internal battle.
Fang noticed immediately. He set down his brush.
"There is someone else, Doctor Li."
Li Chunfeng hesitated.
"I have one more friend, Sir Fang. He is exactly my age." He paused, as if weighing whether to say the next part. "Honestly, his mathematical talent completely destroys mine."
Fang's eyebrows rose. That was a strong claim coming from the man the future texts called a genius.
"Furthermore," Li Chunfeng continued, "he is an absolute master of musical theory. He understands classical literature. He is brilliant at hydrology and geographic mapping."
Fang Xuanling instantly leaned forward, his political instincts flaring to life.
"Oh? Who is this man?"
Li Chunfeng stopped hesitating. He put his friend's name on the table.
"He is currently working as a music researcher in the Hongwen Pavilion. His name is Lu Cai."
On paper, Lu Cai was just a guy who tuned instruments for court musicians.
But Fang deeply respected Li Chunfeng's judgment. If the genius said this musician was a math god, Fang believed him. He carefully brushed Lu Cai's name onto the top of his list.
The recruiting session was over.
Fang smiled and closed the trap.
He formally offered Li Chunfeng the position of Doctor within the new Mathematics Pavilion.
It was not the terrifying Vice Director job. But it was still a huge promotion. It instantly elevated Li Chunfeng 10 ranks up the imperial ladder. It gave him resources, respect, and a safe place to do his research.
This time, Li Chunfeng had absolutely no logical reason to refuse.
He accepted the job.
He was thrilled, but one small detail bothered him.
The Chancellor had tacked on a very specific, strange condition to the employment offer.
Chunfeng scratched his head in confusion.
"Sir Fang, I have to promise to stop messing around with Daoist alchemy?"
Fang Xuanling did not answer.
He simply smiled.
---
The long 10-day winter holiday officially concluded.
The capital city of Chang'an snapped back into its original, frantic rhythm. The recent total annihilation of the Eastern Turkic Khaganate had injected huge wealth and confidence into the empire. The city streets were more prosperous and crowded than ever before in history.
Time flowed forward.
In the middle of the second month, a very strange diplomatic caravan reached the towering gates of Chang'an. The foreigners in the group were notably short in stature, their eyes wide with wonder as they craned their necks to look up at the towering walls of the Tang Empire.