"Why didn't you kill me earlier? If you had, you wouldn't have had to harbour such evil schemes against your mother."

"What about my mother?" Qian Long asked, turning pale.

"You understand."

"So you know everything?"

"No, not everything. Master Yu said the Empress Dowager knew he had helped you and had asked you to repay him, but that you were still unwilling to part with the silver. You have mountains of money. Three million taels should be nothing to you. But you insist on being petty."

Qian Long laughed nervously. He pulled out a handkerchief and wiped away the beads of sweat on his brow. He paced the room to steady himself, then smiled. "You show no fear at all before the Emperor. You are indeed a man of steel," he said.

"What have I to be afraid of? I doubt if you would dare to kill me," said Wen.

"Wouldn't dare?"

"You want to kill me because you're afraid your secret will be revealed but as soon as you kill me, your secret will be impossible to keep."

"Can dead men talk?"

"As soon as I die, someone will open a certain letter and reveal the evidence to the world. Then you will be in a real predicament."

"What letter?" Qian Long asked.

"Before we went to the palace to see you, Master Yu wrote down every detail of the affair and sealed the document in an envelope together with two important pieces of evidence and left it with a friend."

"Was he afraid that something untoward might happen?"

"Of course. How could he trust you? Master Yu told his friend that if we were both to die suddenly, he should open the letter and do what it said, but if one of us was still alive, not to open it under any circumstances. Master Yu has already passed away, so I don't think you'll dare to kill me."

Qian Long wrung his hands, anxiety written all over his face.

"Wouldn't it be worth spending three million taels of silver to buy that letter and the two pieces of evidence?" Wen asked.

"The silver? I had always planned to hand it over and then release you. Write a letter to your friend telling him to bring the letter to me and I will immediately pay up the money."

"Ha, ha. Once I tell you his name, you can send your bodyguards to kill or capture him. Actually, I'm very comfortable here. I would be happy to stay the rest of my life. You and I have the same fate. If I die first, you won't live much longer."

Qian Long bit his lip. "If you won't write the letter, it is of no importance," he said after a pause. "I will give you two days. If you persist in being stubborn, I will have no alternative but to kill you. No-one else will know about it and your friend will think you're still alive. And even if I don't kill you, I can still have your eyes gouged out, your tongue removed, your arms cut off…Think about it over the next two days."

He pushed open the door and walked out. His bodyguards re-assembled around him, and Commander Li saw him out of the Yamen.

Wen was carried back to the dungeon by the Commander's personal guards with Zhang Zhaozhong providing an escort. Once in the cell, one of the guards handed Zhang a letter.

"Commander Li asked me to give you this," he said. Zhang opened and read the letter, then left.

Wen lay on the bed thinking about his wife and friends. He hoped none of them would be harmed if they should attempt a rescue.

Just then, the iron door to his cell opened with a clang and a man walked in. Wen thought it was Zhang returning and did not open his eyes.

The man walked over to the bed. "Fourth Brother," he said quietly.

Wen was stunned. He looked up and saw it was Chen. "Great Helmsman!" he exclaimed, sitting up.

Chen smiled and nodded. He pulled two steel files from his pocket, and began filing at Wen's manacles. After a few strong strokes, a series of light scratches appeared on the surface, but the file was ruined. The manacles were made of a specially-cast steel brought from the West, and an ordinary file was useless against it.

"Great Helmsman, only the finest of swords could break through these chains and manacles," said Wen.

Chen remembered the battle with Zhang Zhaozhong at the Yellow River crossing and how sharp Zhang's 'Frozen Emerald' sword had been.

"Does Zhang guard you night and day?" he asked quickly.

"He's never more than a step from me. He only left a short while ago."

"Good. We'll wait for him to return and steal his sword." Chen threw the files under the bed.

"It's possible I won't be able to get out of here," Wen said. "The Emperor wants to silence me because he's afraid I will reveal his secret. I had better tell you what it is, Great Helmsman, so that no matter if I live or die, there will be no delay."

Chen nodded.

"The night I went to the Imperial Palace with Master Yu, Qian Long was very surprised to see us. Master Yu said: 'A lady from the Chen family in Haining asked me to come,' and handed him a letter. The Emperor's face went pale as he read it, and he told me to wait outside. The two of them then talked for about two hours before Master Yu finally came out. On the way back, he told me the Emperor was not a Manchu at all, but a Chinese and also your elder brother."

Chen started in shock. "That's impossible," he said firmly. "My brother is in Haining."

"Master Yu said that on the day the Emperor Yong Zheng's wife gave birth to a girl, your mother by coincidence also gave birth to a boy. Yong Zheng ordered the Chen family's child to be brought for him to look at, and when it was returned, it had become a girl. The boy is now the Emperor Qian Long…"

Before he could finish, they heard the sound of footsteps in the corridor and a guard came in.

"What is it?" asked Chen.

"Master Zhang is returning. Commander Li is unable to detain him further and asks you to leave quickly."

"Thank you," Chen replied. His left hand shot out and touched a Yuedao point on the guard's body. The guard toppled to the floor without a sound, and Chen pushed him under the bed.

"With Zhang on his way, I don't have time to give you all the details," Wen continued. "Master Yu knew the Emperor was Chinese and went to urge him to overthrow the Manchus and restore China to the Chinese while remaining as Emperor himself. Qian Long appeared moved by the appeal, and asked Master Yu to bring evidence before making a decision. But as soon as Master Yu returned home, he fell ill and never recovered. His last wish was that you should be the Great Helmsman, and he said to me that this was a good opportunity for us to restore the honour of the Chinese people. The Emperor is your elder brother. If he is unwilling to overthrow the Manchus, then everyone will support you to take his place."

His words left Chen too stunned to speak. He thought back to when he had first seen Qian Long by the lake and afterwards crying before the tomb of his parents. Could it really be that the Emperor was born of his own mother and father?

"I understand your mother wrote down the full details of how the Emperor Yong Zheng swapped the girl for your brother in a letter which Master Yu gave along with several other pieces of evidence to your teacher, Master Yuan, to look after."

"Ah, so when the Twin Knights went to see my teacher this summer, they were carrying these things to him on Master Yu's orders?"

"That's right. It was so secret that not even you could be told. All that Master Yuan knows is that they are extremely important, but he does not know what they are. Just before Master Yu passed away, he said that after you became Great Helmsman, you should open the letter and make your plans accordingly. But I stupidly allowed myself to be captured and risked the whole enterprise. Great Helmsman, if you can't get me out today, you must go to the Muslim regions as quickly as possible to see your teacher. You must not endanger the great cause of restoration just for my sake."