When the small door sprang open, both Yan Qing and Bai Jin were left speechless for a moment.

Bai Jin recovered quickly, his face lighting up with delight. “A hidden compartment.”

Yan Qing said, “This hidden compartment sits directly behind Song Zixian’s chair — he could reach it easily by simply swiveling around. He really did keep his most important things right where he could see them.”

“Miss Yan, there’s a code required inside.” Bai Jin’s expression shifted from elation to anxiety. “What do we do?”

They had finally found the hidden compartment, only to be blocked by a lock combination. Song Zixian was dead, and without the code, the compartment could not be opened.

“Can we force it open?”

“No. There’s a steel safe fitted inside. Even if we break through the bookshelf and the wall, all we’d have is the safe itself.”

Yan Qing considered. “Perhaps we can work out the code.”

“Work it out?” A six-digit combination yielded a million possible arrangements. Testing them one by one would take who knew how long.

“Do you remember the safe that Song Meimei stole from Song Zixian? By all logic, Song Zixian would never have told Song Meimei his combination. So how did she open it?”

“You mean she guessed it too?”

“That’s the only way she could have done it.” Yan Qing tapped her index finger lightly against her knee. “Generally speaking, when ordinary people set a code, they follow a predictable pattern — a birthday, an anniversary, an auspicious number, or some date that holds personal significance.”

“Would Song Zixian really use something that simple?”

“Song Zixian was also an ordinary person, in the end. A code like that is both convenient and easy to remember.” Yan Qing asked, “Do you still have Song Zixian’s records?”

“I do.” Bai Jin pulled several pages of documents from his bag.

Yan Qing first tried Song Zixian’s birthday. It didn’t work.

“What about the date he joined the bank?” Bai Jin pointed to several strings of numbers on the documents. “His start and departure dates at the Tongde branch and at the main bank.”

“No.” Yan Qing shook her head after trying.

“What about the day the Chengguan Railway funds were robbed? That must have been a significant date for Song Zixian.”

“That makes sense.” Yan Qing quickly entered the date of the robbery. It was wrong as well.

The two of them tried several more combinations in turn, but none of them opened the safe.

Bai Jin grew despondent. “What on earth did this Song Zixian set as his code? By all rights, there are only so many dates that could mean something to him — how is it that none of them are right?”

“Perhaps we’ve overlooked something.” Yan Qing let out a quiet sigh, pressed one hand to her forehead, and closed her eyes to think.

What if Song Zixian had gone against all convention and invented a code of his own choosing? In that case, they could rack their brains forever and never land on it.

Still — as long as there was any lead to follow, it had to be tried.

When Yan Qing opened her eyes, her gaze fell, without quite intending to, on Song Zixian’s desk. A picture frame sat there, face-down.

She picked it up, and a black-and-white photograph came into view.

It showed a family of four, at peace with one another. In the center sat a man in a long robe — unmistakably Song Zixian, though much younger, perhaps only in his thirties. Beside him sat a woman with a rounded bob, dressed in a qipao — his wife, most likely. Standing behind the two of them were a boy and a girl, both appearing to be in their early teens.

“Is this Song Meimei?” Yan Qing asked.

“It is.” Bai Jin remarked, “She was a beauty even when she was young.”

“And this must be Song Zixian’s son?”

“According to Liu Cui and Song Meimei, Song Zixian’s son went abroad to study eight years ago and has not been heard from since — there are no recent photographs either. But looking at his features, especially the resemblance to Madam Song around the eyes and brows, he must be Song’s son.”

“Did something happen to him, or did he simply not wish to return?”

“That’s unclear.”

Yan Qing noticed that the face of Song Zixian’s son in the photograph was somewhat blurred — the result, it seemed, of being touched over and over again across many years.

A burst of realization lit up her mind, and her voice carried a note of excitement she could barely contain. “Do you have the son’s date of birth and the date he left the country?”

“That would have to come from Liu Cui — she should be able to remember.”

“Wait here for me. Go to Liu Cui right now.”

“On it.” Bai Jin sensed a faint glimmer of light breaking through, and wasted no time setting off from the bank.

Yan Qing gazed at the photograph before her, the corners of her lips curving gently upward.

Her guess should be right. Song Zixian, miser though he was, was at the end of the day a father — and this father had loved his son deeply. After his son left, he had traced his face in the photograph every single day, until that spot had worn rough and indistinct.

About half an hour later, the deputy director knocked at the door. “Miss Yan, you have a phone call.”

Bai Jin had called into the bank and passed two strings of numbers to Yan Qing.

Yan Qing first tried the son’s birthday. Wrong. Then she entered the date he had gone abroad. After pressing the final digit, the safe clicked open with a sharp snap.

Only then did she finally understand how Song Meimei had managed to open that safe of hers — she must have spent several days guessing before she, too, thought of her brother.

Inside the safe were documents, deposit certificates, and a quantity of gold and silver jewelry, far greater in number than what Song Zixian had kept at home.

Yan Qing had no interest in the money, and went straight to the documents, opening each one in turn. When she opened the folder marked with the name of Fushan Bank, her expression brightened.

Fushan Bank was a foreign institution with a rigorous management system. The document before her was a safety deposit box rental agreement, written out with perfect clarity: the lessee was renting box number 1867 at Fushan Bank for a term beginning on March 19th of year 201 and ending on September 19th of year 203, a period of three years and six months, during which the box could not be opened early.

At the bottom of the agreement, beside Song Zixian’s signature, three characters were written in unmistakable clarity: Han Qiren.

This was a safety deposit box entered into jointly under both their names. The agreement had been drawn up in triplicate — one copy each for the bank and the two lessees.

The agreement stipulated that upon the expiration date, any party holding their copy of the agreement could retrieve the safe from the bank’s vault without both parties being required to present themselves simultaneously.

Yan Qing snapped the document shut with excitement and carefully slipped it into a folder.

With Han Qiren’s fingerprints from the scene of the crime, and now this signed agreement, even if he were to invoke the Commander’s name, it would do nothing to clear him of guilt.

This case was as good as sealed. There was no escaping it.

Just as Yan Qing was storing the document, a dark figure soundlessly pushed open the door, a blade in hand flashing a blinding arc of light.

With her back to the door, Yan Qing had no idea anyone was approaching. She only looked up after she had finished putting the documents away.

The glass panel on the bookshelf door reflected a face she did not recognize.

Just as Yan Qing felt a sudden jolt of alarm, the figure abruptly toppled backward, followed by a muffled grunt, and did not rise.

She spun her wheelchair around quickly, and found the deputy director smiling calmly at her. The figure in black lay unconscious on the floor, a sharp blade still clutched in his hand.

A large question mark formed on Yan Qing’s face. “You — who are you?”

“Miss Yan, I am one of Director Shi’s people.” The deputy director replied with respectful composure. “The Director instructed me to ensure Miss’s safety while at the bank.”

“You’re one of Shi Ting’s people?” Yan Qing’s eyes grew even wider.

The deputy director offered a smile. “Bai should be back soon. I’ll leave this one for Bai to deal with when he returns. My apologies — I hope the incident didn’t startle you, Miss.”

Yan Qing could not begin to imagine how vast a network Shi Ting had built in the shadows, that even the director of Zhongqi Bank was in his service.

No wonder he had been so certain, at the time, that Song Zixian’s safe had not been stored in Zhongqi Bank’s vault.

The deputy director was perfectly courteous. “Miss Yan need not worry — the man just now was one I deliberately allowed inside.”

Yan Qing glanced at the figure on the floor. “A witness?”

The deputy director nodded. “Knowing that you are gathering evidence, Han Qiren will certainly have people watching your movements from the shadows. I saw an opportunity to capture one of them.”

“That is a clever approach. But might it not tip him off?”

“Han Qiren has dispatched a great many people — the disappearance of one won’t draw his attention. However, I must respectfully ask Miss Yan not to mention what just occurred to Director Shi.” The deputy director was earnest in his plea. “If the Director were to learn that Miss had been placed in even the slightest danger, I would face consequences.”

The image of Shi Ting’s solemn face rose before Yan Qing, and she could not help smiling. “Very well.”

Not long after the deputy director left, Bai Jin returned. Hearing that someone had attempted an attack, he immediately asked whether Yan Qing had been hurt. Yan Qing told him the deputy director had arrived very quickly, and the man had been caught before he even made it through the door.

“Did you know the deputy director was one of our own?”

Bai Jin gave a sound of assent. “I knew.”

Seeing the curiosity in Yan Qing’s eyes, though she said nothing further, he offered the explanation himself. “Seventh Brother’s network of connections in Shun Cheng could only be described as a vast web, spread across every corner.”

So even now, confined to his courtyard under house arrest, this sprawling web of contacts continued to operate — each piece of it quietly fulfilling its role.

Yan Qing could not help marveling. The man she cared for could be summed up in a single phrase: a dragon does not linger in shallow waters.

After bringing the evidence back to the Military Police Division, everyone gathered together for a case briefing.

Bai Jin spoke with full confidence. “We lifted Han Qiren’s fingerprints from the toothbrush cup in Song Zixian’s home. At the same time, we found this agreement in his office. The agreement shows that Song Zixian and Han Qiren, acting together, deposited a safe into a safety deposit box at Fushan Bank. Barring any surprises, that box contains the gold bars taken in the Chengguan Railway robbery three years ago.”

Zheng Yun took the copy of the document and glanced over it. “The expiration date is September 19th of year 203 — that’s the day after tomorrow. We only have one day to bring in Han Qiren.”

“Exactly. If we can’t get our hands on what’s in that box, all this evidence can still be argued away by him.”

“With Seventh Brother gone, there’s no way we can arrest him.” Zheng Yun’s brow was furrowed. “To arrest Han Qiren, Seventh Brother has to be the one to handle it personally. The man backing Han Qiren is the guard regiment.”

Bai Jin scratched his head. “What do we do? How do we get the Commander to release Seventh Brother?”

From a corner where she had been sitting quietly without a word, Yan Qing suddenly spoke. “Perhaps there is one way to get the Commander to release Shi Ting.”

Every expectant gaze in the room turned toward her at once.

“What way?”

—