The city of Acre seemed to hang in mid-air, suspended between the desert sky and the waters of the Mediterranean. Its walls and towers shimmered in the afternoon heat, wavering like the domed tents in the wind that blew in from the sea. An army of men - the army of Salah ad-Din - were camped on the plain around the city. The banner of the crescent moon was everywhere.

The wizard Wu Gu Xian gazed down at the city from atop his camel. He had journeyed for many months along the Silk Road at the behest of his master, and now his destination was finally in sight. On his journey from Cathay, the wizard had faced many dangers and privations, but none of this mattered any more. He offered up a prayer to his ancestors, thanking them for his good fortune, then tapped the flanks of his mount with the goad he carried.

"Ble-ee-eh!" The camel bleated loudly and began to trot down the trail towards the city. Wu Gu Xian clung to the beast's reins, guiding it down what he hoped was the easiest path. Stones scattered beneath the camel's paws, but it showed no sign of losing its footing. While it made for an uncomfortable ride, the wizard had to admit that his mount had been a faithful companion throughout his journey.

As Wu Gu Xian made his way down, he noticed a pair of horses leave the camp and come galloping towards him. He brought the camel to a halt and waited for the riders to catch up with him.

"You!" The first of the riders called out to him. "Who are you? And what is your business here?"

What a barbarous tongue, Wu Gu Xian thought before responding. "I am a traveller from the east. A scholar. I have come here to study the texts held at the Jama Masjid."

The two riders glanced at each other. "Can you prove what you say?" the first one asked. Before Wu Gu Xian could answer him, the second rider prodded with his lance at the bags draped over the camel's flanks.

"What do you have in there, scholar?"

Wu Gu Xian glanced down from his seat. "Food. Water. My books."

The second rider reached out to undo the strap that held one of the bags shut. "Then you will not mind me taking a look, scholar."

Wu Gu Xian shrugged. "I have nothing to hide from you."

The rider opened the bag and started to rifle through its contents. Wu Gu Xian turned his attention back to the first of the two riders. "There will be nothing to tax in there - unless the ruler of this city places a tax on knowledge?"

"You must forgive us. We have to be wary of spies."

"Spies?"

The horseman nodded. "The armies of the Crusaders are on the march. They have laid waste to the land and put many to the sword - all in the name of their pope!" The rider turned his head, hawked and spat into the sand. "Our sultan fears that they will come here next, and that they will send their spies ahead to clear the way."

Wu Gu Xian nodded in sympathy. "I understand. Search away." He ran his hand over his chest, feeling the reassuring form of the bamboo scroll case under his robes.

"Nothing that a scholar would not have," the second rider called out to his companion.

"Well, scholar, you may pass."

Wu Gu Xian raised his right hand in salute. "Thank you."

It was not long before Wu Gu Xian passed through the gates of the city and made his way through the narrow streets. Every so often he would pause to ask a passer-by directions. Most of them shook their heads and shrugged, but one gave him the answer he sought. "You mean old Yusuf?" the urchin replied eagerly. "I can take you to him for three copper coins.

Wu Gu Xian fished out five coins from his purse. "Two now. Three more when I am satisfied that you have brought me to the right man."

The urchin looked suspiciously at the proffered coins. "I don't recognise those," he sniffed.

The wizard passed two of the coins down to the boy. "I have promised you these already, so take them and satisfy yourself."

The child took the coins, polished them against his shirt and held them up to the light. He grinned. "Follow me."

Wu Gu Xian followed his guide through the streets and to the entrance to a small courtyard. A colonnade provided shelter from the sun, while a fountain brought a welcome hint of moisture to the air. Doors led into the buildings that surrounded the quiet space, while curtained windows looked down from above. Wu Gu Xian was sure that he saw a hand pull one of the curtains back.

"Here we are," the urchin said, and held out his hands. "Pay me the three coins you promised me."

Wu Gu Xian heaved himself down from his camel. "We shall see." He strode forward into the courtyard.

A tapping noise - the sound of wood against stone - could be heard above the bubbling of the water spilling from the fountain. An old man, his hair grey and back bent, shuffled into the courtyard. "A visitor? We don't get many of those." He paused, leaning on a stick to support.

"You are Yusuf bin Waziri?" Wu Gu Xian asked.

The old man nodded. "And you are?"

"Wu Gu Xian."

The wizard felt a tugging at his belt. "Pay me," his guide demanded. Wu Gu Xian handed over the remaining coins, and the boy scampered away, laughing.

"And what do you seek?" bin Waziri asked. Wu Gu Xian reached under his robe and pulled out a dagger with a flame-like hilt. He held the weapon up for inspection. "I understand," the old man said. "Come inside. I am sure you would like some refreshments after your journey. And then we can talk."