As he trotted through the darkness, Jelaudin stared at the fires ahead of him. The men running at his stirrups were exhausted, but he had pressed his father for one more massed charge, knowing that their best chance lay in catching the Mongols asleep. He seethed at the thought of his father’s precious guard still barely blooded. The shah had refused his demands to have them accompany him, just when they would have justified their existence. Jelaudin cursed his father and Khalifa too, for losing the cavalry, then pressed away his anger to concentrate. Just one sweep through the enemy camp could be enough to break them at last. The moon was hidden by clouds and Jelaudin rode slowly over broken ground, waiting for the uproar that would follow.

It came sooner than he expected, as enemy scouts blew warning notes before they were cut down. Jelaudin drew his sword and risked his neck with a faster pace. The running men fell behind as he aimed his mount at the Mongol fires.

The khan had made only a rough camp after days of fighting. Jelaudin saw the left flank was a mass of lights, revealing the presence of many men. The nights were cold and they would be clustered close to the flames. On the right, the night fires were more widely spaced, dwindling to just a few points of light on the furthest edge. It was there that he led his men, racing to take revenge for the battering they had suffered.

He heard the Mongols rise against the attack, howling in their mindless anger. Jelaudin shouted a challenge into the night, echoed by his men. The fires came closer and suddenly there were men on all sides and the forces met. Jelaudin had time to shout in surprise before his stallion was cut from under him and he went flying.

Tsubodai waited, with Jochi, Jebe and Chagatai. It had been his idea to arrange the fires to draw in a careless enemy. Where the lights were thick, he had just a few men tending them. In the darkness there, veteran tumans clustered with their ponies, far from warmth. They did not heed the night cold. For those who had been born on the frozen plains of home, it was nothing to them. With a great shout, they charged the Arab ranks coming in.

As the two forces came together, the Arabs were sent reeling, smashed from their feet by men who had fought and trained from the earliest years. Their right arms hardly tired as they punched through the enemy and rocked them back. Tsubodai bellowed orders to advance and they trotted forward, shoulder to shoulder, their mounts stepping delicately over dying men.

The moon rose above them, but the attack was broken quickly and the Arab force sent streaming back to their main camp. As they ran, they looked over their shoulders, terrified that the Mongols would ride them down. Not half of their number made it clear, though Jelaudin was one of them, humiliated and on foot. He staggered back to his father, still dazed from the chaos and fear. In the distance, the Mongols finished off the wounded and waited patiently for the dawn.

Shah Ala-ud-Din paced his tent, glaring at his eldest son as he turned. Jelaudin stood nervously, wary of his father’s anger.

‘How did they know you would attack?’ the shah snapped suddenly. ‘There are no spies in the ranks, not here. It is impossible.’

Still smarting from his failure, Jelaudin did not dare to reply. Privately, he thought the Mongols had merely prepared for the possibility of an attack, not known of one, but he could not seem to praise them while his father raged.

‘You see now why I did not give you my personal guard?’ the shah demanded.

Jelaudin swallowed. If he had ridden in with five hundred horsemen, he did not think the rout would have been so easy or so complete. With an effort, he strangled a retort.

‘You are wise, father,’ he said. ‘Tomorrow, they will take the fight to the enemy.’ He fell back a step as his father rounded on him and stood close enough for the bristles of his beard to touch his son’s face.

‘Tomorrow, you and I are dead,’ the shah snarled. ‘When the khan sees how many men I have left, he will fall on us and make an end to it.’

Jelaudin was relieved when he heard a throat cleared at the entrance to the tent. His father’s body servant, Abbas, stood in the lamplight, his eyes flickering from father to son and judging the mood within. Jelaudin made an impatient gesture for the man to leave, but Abbas ignored him, coming in and bowing to the shah. Jelaudin saw he carried a sheaf of calfskin vellum and a pot of ink and he hesitated before ordering the man out.

Abbas touched his forehead, lips and heart in respect to the shah before placing the writing materials on a small table to one side. Jelaudin’s father nodded, his fury still evident in his clenched jaw and flushed skin.

‘What is this?’ Jelaudin said at last.

‘This is vengeance for the dead, Jelaudin. When I have put my name to it, this is an order for the Assassins to rid my land of this khan.’

His son felt a weight lift from his shoulders at the thought, though he repressed a shudder. The sect of Shia fanatics had a dark reputation, but his father was wise to bring them in.

‘How much will you send them?’ he said softly.

His father bent over the thick parchment and did not reply at first as he read the words Abbas had prepared.

‘I do not have time to negotiate. I have offered a note for a hundred thousand gold coins, to be redeemed from my own treasury. They will not refuse such a sum, even for a khan’s head.’

Jelaudin felt his hands grow clammy at the thought of so much gold. It was enough to build a great palace or begin a city. Yet he did not speak. His chance to break the Mongols had been wasted in the night.

Once the shah had signed the note for gold, Abbas rolled the thick sheets and bound them with a strip of leather, tying the knot expertly. He bowed very low to the shah before he left the two men alone.

‘Can he be trusted?’ Jelaudin said as soon as he was gone.

‘More than my own sons, it seems,’ the shah replied irritably. ‘Abbas knows the family of one of the Assassins. He will see it safe to them and then nothing will save this dog of a khan who has shed so much of my people’s blood.’

‘If the khan dies tomorrow, will the gold be returned?’ Jelaudin asked, still thinking of the vast wealth his father had given away in just a moment. He sensed the shah walk to him and turned his head from looking at the tent’s entrance.

‘Unless Allah strikes him down for his impudence, he will not die tomorrow, Jelaudin. Do you not understand even now? Did you not see as you came back to my tent?’ He spoke with a flat intensity that Jelaudin could not understand and the younger man stammered as he tried to reply.

‘See… what? I…’

‘My army is finished,’ the shah snapped. ‘With the men you lost tonight, we have hardly enough left to hold one of his damned generals in the morning. They have reduced us to less than thirty thousand men and even if the Otrar garrison appears at this moment, we have lost. Do you understand now?’

Jelaudin’s stomach tightened in fear at his father’s words. They had fought for days and the slaughter had been terrible, but the field of battle was vast and he had not known how bad the losses had been.

‘So many dead?’ he said at last. ‘How is it possible?’

His father raised a hand and, for a moment, Jelaudin thought he would strike him. Instead, the shah whirled to pick up another sheaf of reports.

‘Do you want to count them again?’ he demanded. ‘We have left a trail of corpses for a hundred miles and the Mongols are still strong.’

Jelaudin firmed his mouth, making a decision.

‘Then give command to me, for tomorrow. Take your noble guard and travel back to Bukhara and Samarkand. Return in the spring with a fresh army and avenge me.’