As his men turned their bows on the Arab infantry and crumpled them, Samuka shook his head to clear it. Foot soldiers could not trouble Genghis, he reminded himself. One sharp blast on a scout horn had his men turning their horses to him.

Samuka used his sword to point and kicked his mount forward, passing close enough to the fiery gate to feel its warmth on his cheek. Even as he did so, the city vomited fresh soldiers down the ropes to replace the dead, but no enemy remained to face them.

It was strange to leave a battle behind. Otrar was not a small city and Samuka saw blurred figures on the walls as he and his men raced along in their shadow, alone with the rhythm of hooves and the smell of smoke. He did not know how long the supply of Chin fire oil would last and he suffered at the thought that a better thinker would have found a way to hold both gates.

He heard Ho Sa’s men before he saw them and Samuka drew his bow from its holder, an extension of his strong right arm. The walls rushed by and the sound grew until he came upon a scene of bloody chaos.

Ho Sa had struggled to hold the second gate, Samuka saw at a glance. Without the catapults, he and his men had been driven back by waves of soldiers. They roared at the Mongols, berserk to the point of pulling arrows from their own flesh as they marched and leaving bloody footsteps on the ground.

Samuka’s last thousand men hit them from behind, cutting into the Arab regiments in an impact so colossal that they smashed almost through to Ho Sa’s core of warriors in one sweep. Samuka felt them slowing around him as horses were killed or hemmed in too close by dying enemies. He reached for an arrow but found nothing and threw down the bow as he drew his sword once more.

He could see Ho Sa fighting for every step as the warriors were pushed back. Samuka grunted and hacked with all his strength to reach him, but more and more men came rushing round the city after him and he felt as if he were being swallowed in a dark and roaring sea.

The sun was dipping towards the west. Samuka realised he had been fighting for hours, but it was not long enough. The second gate was a hundred paces away and no flames burned there. He could see horsemen coming out and they did not join the others. Samuka cried out in rage and despair as they streamed away in a ragged column. Even a small number of cavalry hitting the khan’s rear could mean the difference between life and death.

Samuka blinked blood out of his eyes as he kicked a man away from his right stirrup. Of the men Khasar had left him, just a few hundred still lived. They had killed many more than their own number, but this was the end. Somehow, Samuka had believed he would survive it, despite the odds. The thought of his body cooling on the ground was beyond his imagination.

Samuka shouted Ho Sa’s name across the swarming heads and hands of men clutching at him. He could feel their fingers tugging at his legs and he kicked wildly and slashed with his sword as Ho Sa saw him. Perhaps for a moment, the Xi Xia officer thought he was calling for aid, but Samuka gestured with his sword after the fleeing cavalry. As Ho Sa turned to follow the gesture, Samuka saw him gashed across the neck, blood gushing as he collapsed.

Samuka howled in fury as he brought his blade down on fingers digging into his thighs. Bearded faces clustered so thickly around him that his horse came to a halt and Samuka felt a sudden calm, mingling with surprise. Khasar had not come back. He was lost and alone and all his men were dying.

Hands gained purchase on some part of his armour and, to his horror, Samuka felt himself begin to slip. He killed another man with a wild swing, but then his arm was trapped and the sword torn from his hand. His horse lurched with unseen wounds and the men around him were so close that he could see their red throats as they yelled. Samuka slid into the mass, still flailing. The setting sun vanished as he fell at the feet of stamping, stabbing men. The pain was worse than he had feared. He told himself that he had done all he could, but it was still a hard death and the garrison of Otrar was out.

Even over the noise of galloping hooves, Tsubodai could hear the crackle of feathers at his ear as he drew his bow. He rose from the saddle and sighted on the front legs of an elephant that was coming at him like a landslide. On every side, his men copied the action and, when he released, a black blur of arrows snapped out. None of the warriors had to think about their actions. They had trained for it ever since they had been tied to a sheep and taught to ride at two or three years old. Before the first arrows hit, they had a second on the string. Powerful cords of muscle swelled in their right shoulders as they pulled back again.

The elephants bellowed and reared in pain, swinging their heads from side to side. Tsubodai saw shafts sink into the massive grey legs, catching them in full stride and breaking the rhythm of the charge. Half of the enormous animals stumbled as a leg buckled. Others raised their trunks and showed yellow tusks in enraged challenge. If anything, the speed increased, but the second wave of arrows cracked out and the elephants shuddered with the impacts. Arrows snagged between their legs, wrenching at wounds.

Tsubodai reached automatically for another arrow, but his fingers closed on an empty quiver. He was almost at the shah’s cavalry by then and he dropped his bow back into the stiff leather fold on his saddle and raised his sword over his right shoulder, ready to chop down.

The men around him loosed one last shaft at the approaching lines and Tsubodai stood in his stirrups as he saw the closest elephants rear on their hind legs, wild with pain. Their handlers screamed, beating wildly as they were spun around. His heart seemed to slow as he saw one of them plucked off a broad back and thrown to the ground with appalling force. The elephants turned in agony from the line of galloping warriors, knocking down horses and men.

Tsubodai shouted in triumph as the massive animals retreated blindly into the shah’s ranks. They cut lines through the advancing soldiers as if they waded through thick grass, using their tusks to toss aside fully grown men. Nothing could stop them in their madness. In just moments, Tsubodai faced broken front ranks, dazed and bloodied by the passing beasts. Some of the Arabs recovered quickly enough to send their own arrows whirring from double-curved bows. Mongol warriors and horses were cut down, but the others showed their teeth and rode. In the last instants before the forces met, Tsubodai picked his man and guided his pony with knees alone.

The Mongol warriors went over the first line into chaos. Tsubodai took the head of one soldier, then almost lost his seat as another aimed a blow at him and he ducked under it. As Tsubodai rose, he held out his blade and his shoulder wrenched at the impact against armour. His low stance and weight kept him in the saddle as an Arab fell and Tsubodai found himself in one of the bloody tracks the elephants had left. He could still see them charging away, tormented and blind to the destruction in their wake. Tsubodai silently thanked the monstrous animals as he looked around for another enemy.

The shah’s ranks had been shocked into immobility by the rampaging elephants. Arab archers scattered, dying as they bawled orders in fear while the Mongols came in hard, taking wounds without a sound while they hacked and chopped. Good blades were ruined on Arab armour, but their arms rose and fell without respite, and if a shield stopped one strike, they whipped another in above or below, cutting legs and throats. They were faster than those who faced them. Tsubodai clashed with a huge, bearded Arab, fighting in a mindless frenzy. Tsubodai could smell the man’s sweat as he used his pony’s shoulder to knock him off balance. In the instant before he was past, Tsubodai saw the curved sword had no guard and let his blade slide, cutting three fingers cleanly so that the weapon spun away. The shah’s men were large and Tsubodai wondered if they had been picked for their strength more than skill. Their blows hammered at his warriors, but again and again, Mongols ducked or swayed away, cutting back where they could and moving on. Many of the shah’s soldiers took three or four wounds before blood loss felled them.