Karakorum was as strange a mixture of squalor and splendor, of barbarian simplicity and Byzantine intricacy, as ever existed on the face of the Earth.

During the time of Genghis Khan this city of tents and yurts had become the capital of the world, where the conquered nobility of China and Islam came to serve the Mongols as slaves, where the treasures of all Asia flowed into the hands of men who had begun their lives as nomadic tribesmen.

While he lived, Genghis Khan had forbade the building of permanent structures in his capital. The tents and carts and yurts of old were good enough for him, in this encampment by a serene river, where good grass grew to feed his most important treasure — the herds of horses that carried his warriors to the farthest corners of the world.

It was the horses that marked the outskirts of Karakorum. Huge corrals ringed the Mongol capital, holding tens of thousands of the small, tough ponies of the Gobi. Their neighings could be heard for miles. Their stirrings raised clouds of dust that could be seen from two day’s ride away. It reminded me, as we approached the capital one chilly morning, of the smoke and smog that marked industrial cities in the twentieth century.

Ogotai was the High Khan, and he ruled with the administrative aid of Chinese mandarins who understood writing and record-keeping. As Agla and I neared the city, we could see that buildings of sun-baked mud and even stone were rising around the ordu, the pavilion of tents that marked the headquarters of the High Khan. Most of these new buildings, I quickly learned, were churches or temples. The Mongols were tolerant toward religions, and priests of every type crowded the bursting city: Buddhist monks in their saffron robes, turbaned imams from the Moslem lands, Nestorian Christian priests, Chinese Taoists in their silks and brocades, and many others whom I could not recognize.

We were stopped by the guards who stood on duty where the road entered the maze of buildings that marked the outskirts of Karakorum. A silk-robed Chinese examined the paper that Subotai had given me — a paper written by one of Subotai’s Chinese aides — and commanded a warrior to find us living quarters. The warrior mounted his pony and led us silently through the bustling hodgepodge of Karakorum. Treasure caravans were unloading; men and women milled about everywhere. There was no order to the layout of the buildings, no preplanned streets as such, merely meandering paths of hard-beaten earth between the haphazardly constructed buildings. Every language in the world was being spoken here, and often shouted or screamed, as merchants haggled over prices or offered wares ranging from pomegranates from China to swords of Damascus steel so fine that you could bend the blade over double without snapping it.

We were installed in a small, one-story house made of adobe. Its door opened onto the broad empty space that surrounded the High Khan’s ordu. From the narrow window of the front room we could see the pavilion of white tents, hung with silk and cloth-of-gold, and the warriors who stood guard before the entrances. As they had in Hulagu’s camp, forty degrees of longitude to the west of here, the Mongols had two big bonfires blazing in front of the main entrance to the High Khan’s tent. To ward off evil spirits.

There was an evil spirit already in this city, I knew. Ahriman must have arrived before us. Had he won the ear of the High Khan? Would I be the victim of another assassination attempt once I presented myself to Ogotai?

But even those worries failed to keep me awake. After so many weeks of hard riding, Agla and I collapsed into the feather bed and slept for almost twenty-four hours.

I awoke to a sense of danger.

My eyes snapped open and every sense was instantly alert. Agla lay slumbering beside me, her head nestled against my shoulder. Without moving my head, I scanned the little bedroom. It had no windows and only one doorway, hung with a curtain of beads, about two feet to the left of the bed. It had been a slight rustling of those beads that had awakened me, I realized.

I held my breath, listening. My back was turned to the doorway, so I couldn’t see it unless I turned my head, and I didn’t want to do that for fear of alerting whoever it was that was standing on the other side of the beaded curtain.

The curtain rustled again and I saw, in the dim early morning light, a gray shadow slide against the far wall of the bedroom. Then another. Two men, wearing the conical steel helmets of Mongol warriors. The first shadow raised its arm and I saw the slim blade of a dagger in its hand.

I rolled across the sagging bed and hit them both at the same time with a body block that sent them staggering into the other wall. Pushing myself up from the floor before they could gather their wits, I twisted the dagger out of the first one’s hand. As it fell clattering to the floor, I swung as hard as I could at the neck of the second assassin with a backhand chop. Behind me I heard Agla scream. The first warrior was scrambling to his feet now and reaching for the sword at his waist. I punched at his heart and felt ribs breaking. As he doubled over, I drove a knee into his face. He bounced off the wall and slid to the floor.

Turning, I saw Agla standing naked on the far side of the bed, a dagger of her own in her left hand, her lips pulled back in a savage snarl.

“Are you all right?” We both asked at the same instant. Then she laughed, shakily, and I took a deep breath and calmed my racing heart.

She wrapped the bed quilt around her as I squatted down to examine the would-be assassins. Both were dead. I had driven a sliver of bone from the nose into the brain of the first one, and the second one’s neck was broken.

Agla came around the bed and knelt beside me. Her eyes were round with awe.

“You killed them both, with your bare hands!”

Nodding, “I didn’t mean to. I wanted to find out who sent them.”

“I can tell you that. It was the Dark One.”

“Yes, I think so, too. But it would be better to know for certain.”

A warrior burst through the open front door, sword in hand. “I heard a scream!” Then he saw the two dead men sprawled on the floor. He looked at me, then back at the would-be assassins.

I expected that he would be angry that two of his fellow Mongols had been killed by an alien. I tensed myself for another attack. Instead, he gaped at me in wonder.

“You did this?”

I nodded.

“Alone? Without weapons?”

“Yes,” I snapped. “Now get them out of here.”

Agla, still grasping the quilt around her shoulders, said, “Wait. You wanted to make certain who has sent these killers.”

Before I could reply, she dropped to her knees and peeled back the eyelid of one of the dead men. She stared into it intently, shuddered slightly, and then closed the man’s eye again. Then she turned to the other and did the same. As I watched her, I realized that I was standing stark naked. The heat of fighting and anger was subsiding inside me; I began to feel chilled.

Agla got to her feet and clutched the quilt around her more tightly. “It was the Dark One. I saw it in their eyes.”

“You can see that in the eyes of dead men?” It sounded ridiculous to me.

But she said solemnly, “I can see their entire lives in their eyes. It is a gift of the gods.”

I couldn’t believe that. Agla “saw” what she wanted to see. If she had believed that the assassins had been sent by Hulagu, or the High Khan, or the Man in the Moon, she would have seen that in their eyes, too.

But the warrior believed her. Wide-eyed, both at my fighting ability and at her psychic power, he dragged the two corpses out of the house and shut the door — but not before he ordered us to remain inside until an officer came to speak with us.