Chen grabbed the two girls and leapt backwards several paces, steeling himself to defend them against any attackers. But there was not a sound from the hall. He wondered what kung fu could snatch the weapons from their hands and even suck Huo Qingtong's darts from her pocket.

"We have come only to escape wolves and with no other purpose," Chen shouted into the darkness in the Muslim language. "Please forgive us for any indiscretions we may have committed."

There was no answer but the echo of his own words returning from the far side of the hall.

As Huo Qingtong's initial fright receded, she walked forward again and stooped to pick up her sword. But it was stuck to the floor as if nailed in place. She tried again using all her strength and managed to free it, but a second later, it flew out of her hand again and hit the ground with a clang.

Chen realised what was happening.

"There must be a magnet under here," he said.

"What's a magnet?" asked Huo Qingtong.

"Sailors say there is a big mountain in the far north which attracts pieces of iron which hang free, making them point north to south. When they're on the ocean, they rely on something called a magnetic compass to find their direction."

"And you think there's another magnet mountain under here which is attracting our weapons?" asked Huo Qingtong.

"I think so. Let's try it." He prized up his dagger and placed it and a wooden chair leg on his left hand with his right hand on top to hold them in place. When he took his hand away, the dagger flew to the ground but the chair leg remained motionless.

"So as you see, the magnet is powerful," said Chen, picking up the dagger again and gripping it tightly.

Huo Qingtong walked on a few more steps. "Come here!" she called. Chen ran over and saw a skeleton which was still standing. A few tattered pieces of clothing hung on the frame, and its right hand was holding a white-coloured sword which was stuck into the skeleton next to it.

"It's a jade sword!" Huo Qingtong exclaimed. Chen carefully extracted the sword from the skeleton's grasp, and with its support gone, it collapsed to the floor in a heap.

The jade sword's blade was very sharp, but it was still frail enough to shatter if it clashed with a metal blade. Looking round, they saw there were many other jade weapons of all sizes lying about the hall.

"I know!" Huo Qingtong suddenly said. "The master of this mountain certainly planned things very carefully."

"What?" asked Chen.

"He used this magnet to draw the enemy's weapons away and then his guards finished them off with the jade swords."

Princess Fragrance pointed at a skeleton wearing a metal breast plate. "Look! Some of the attackers were wearing armour. i'll bet they couldn't get on their feet."

"But what I don't understand," Huo Qingtong continued, "is if the guards with the jade weapons killed all the attackers, why did they also die here as well?"

Chen had also been considering that problem, but could think of no explanation.

"Let's go further in and explore," said Huo Qingtong.

"No," Princess Fragrance said. "Let's not, sister."

Huo Qingtong saw the anguished expression on her face and squeezed her arm. "Don't be afraid. Perhaps there are no skeletons over there."

They walked to the other side of the hall and looked into a smaller chamber. But the scene there was even more terrible than in the first hall. Dozens of skeletons were piled about the room, most of them still standing as if alive. Some had weapons in their hands, some didn't.

"Don't touch anything!" said Chen. "There must be some strange reason for them dying like this." They continued on, and passed out of the chamber into a tunnel. After a couple of bends, they came upon a small swing door. As they pushed it open, their eyes were assailed by a bright light. Sunlight poured in from a crack in the ceiling hundreds of feet above into an excuisite jade room which had obviously been carved out of the mountain at this spot to take advantage of the natural lighting.

Although it was only a single shaft of sunlight, the three were very excited at the sight of it. The room they found themselves in had a jade bed, a jade table, jade chairs, all beautifully carved. A skeleton reclined on the jade bed, while in one corner of the room, there were two other skeletons, one large and one small.

Chen extinguished the torch. "We'll rest here," he said. They pulled out their dry rations and water and had a small meal.

"I wonder how long the wolves will wait outside the mountain for us?" said Huo Qingtong. "This has became a contest between us and the wolves, so we will have to make the food and water last as long as possible."

For the past several days, Chen and the two sisters had not had a moment in which they could relax. Now, in this silent jade room, an immense exhaustion came over them and before very long, they fell into a deep, deep sleep.

Zhang and the Three Devils watched the wolves swarm after Chen and the girls with great relief, although they felt a tinge of regret at the thought of two such beautiful girls being ravished by the animals. The four men sat down to rest for a while, then roasted and ate one of the dead wolves left behind. Gu noticed that the supply of tree branches was almost exhausted, and too lazy to go and get more, he threw piles of wolf's dung onto the fire to stoke up the flames. Before long, a column of thick, black smoke was rising towards the heavens.

Just as they had eaten their fill of wolf meat, they noticed a dust cloud approaching from the east. Assuming it to be another wolf pack, they frantically jumped up and ran for the horses. Only two horses were left, both of which had been brought by the Three Devils. Zhang stretched out his hand to take the reins of one of the mounts, but Hahetai lunged in front of him and grabbed them first, shouting: "What do you think you're doing?"

Zhang was about to attack him when he spied Tang and Gu with weapons in their hands closing in. "Why are you getting so excited?" he protested. "They aren't wolves."

The Three Devils turned to look and Zhang vaulted onto the horse's back. Only then did he notice that his lie was in fact the truth: in the midst of the dust cloud was a large herd of camels and goats. He galloped off towards the herd, shouting: "I'll go and have a look!"

After riding only a short way, he saw a rider coming towards him. The rider, an old man dressed in grey, raced up and stopped his mount instantly with a tug on the reins. Zhang marvelled at his horsemanship.

The rider saw Zhang was wearing the tattered uniform of a Manchu military officer and asked in Chinese: "What happened to the wolves?" Zhang pointed west.

By this time, the herd was upon them and in the midst of the dust and noise and confusion, Zhang noticed a bald-headed, red-faced old man and a white-haired old woman riding herd. He was just about to ask who they were when the Three Devils came over and bowed respectfully before the old man in grey.

"We are honoured to meet you again, sir," Tang said obsequiously. "How are you?"

The old man grunted. "Nothing to complain about," he mumbled. It was the Strange Knight of the Heavenly Pool, Master Yuan.

Zhang knew nothing of the old man, but he noted the respect with which the Three Devils treated him.

Master Yuan examined the four of them for a moment, then said: "We are going to catch the wolves. You will all come with me."

They started in fright and wondered if he was insane. But the Three Devils knew his kung fu was formidable and did not dare to refuse.

Zhang, however, emitted a "humph" of astonishment and said: "I want to live a few more years. Sorry, but I will be unable to accompany you." He turned to leave.