'You expect me to burrow myself away to gain a few more heartbeats of life? With my own children being hunted somewhere out there? I would rather die here, on my feet and facing my enemies.'

He meant it, Tsubodai saw, but Ogedai's gaze drifted over Sorhatani and her two sons. For a moment, he locked eyes with his younger brother Tolui. Ogedai wilted under the stares of the family.

'Very well, Tsubodai, but I will return here. Tolui, bring your wife and sons and help me block up the inner door.'

'Take the bow with you,' Tsubodai said, yanking the quiver from his shoulders and tossing it to Ogedai.

The group of five moved back carefully, always aware of the line of sight for an archer in the halls outside. They knew a bowman was waiting in the darkness and they knew the patience of their people, used to hunting marmots on the plains. The archer's field of vision formed a cone that crossed the outer room down the centre.

Without warning, Ogedai darted across the space and Sorhatani rolled, coming smoothly to her feet like a dancer. No arrow came as they reached a safe spot and turned.

Tolui stood on the other side. He had found a place in the shelter of a heavy beam with his sons, his face stiff with fear for them.

'I will go last, lads, understand?' he told them.

Mongke nodded immediately, but Kublai shook his head.

'You are the largest and the slowest,' he said, his voice quavering. 'Let me go last.'

Tolui considered. If the archer was waiting with an arrow on the string and the bow half bent, he could loose a shot in an eye-blink, almost without aiming. Any of the men there would have wagered on the archer over them. The crashing at the door had stopped, as if the men outside were waiting. Perhaps they were. Out of the corner of his eye, he saw Ogedai's wife Torogene beckoning to him.

It was just a few feet across a room, but it had become a chasm. Tolui took a deep, slow breath, calming himself and thinking of his father. Genghis had told him about breath, how men will hold theirs when they are frightened, or take a sudden breath before they launch an attack. It was a sign to watch for in an enemy. In yourself, it was a tool to manage fear. He took another slow breath and his hammering heart eased slightly in his chest. Tolui smiled at Kublai's nervous defiance.

'Do as you're told, boy. I'm quicker than you think.' He laid a hand on each son's shoulder and whispered. 'Go together. Ready? Now!'

Both boys sprinted across the innocent-looking space. An arrow flashed through the gap, passing behind Kublai's back. He fell sprawling and Sorhatani dragged him clear, hugging him to her in desperate relief. She turned with her sons to look at Tolui, who nodded to them, sweat beading his brow. He had married a woman of aching beauty and he smiled at her fierce expression, like a mother wolf with her cubs. The archer was clearly ready and they had been lucky. He cursed himself for not following immediately, before the archer could notch another shaft. He had lost the moment and perhaps his life as a result. He looked around for some sort of shield – a table, or even a thick cloth to spoil the man's aim. The corridor was still silent as the attackers let their bowman work. Tolui took another slow breath, readying his muscles to spring across the gap and dreading the thought of a shaft tearing into him, smashing him off his feet in front of his family.

'Tsubodai!' Sorhatani called.

The general glanced back at her, catching her beseeching gaze and understanding. He had nothing to block the hole for the time they needed. His gaze fell on the single lamp. He hated the thought of plunging the room into darkness once again, but there was nothing else. He swept it up, flinging it through the hole from the side of the door. The crash sent Tolui safely across the gap to his family and Tsubodai heard the thump of an arrow released into the door itself, the aim ruined. Kublai cheered the act and Mongke joined him.

For a few moments, the room remained lit by the flaming oil on the other side, but the men there stamped the flames out and they were left in blackness once again, far deeper than before. There was still no sign of dawn. The furious crashing resumed and splinters flew as the door groaned in its frame.

Tolui worked quickly at the entrance to the inner room. The door there had none of the strength of the outer one. It would not delay the attackers beyond the first few moments. Instead, Tolui kicked out the delicate hinges and began to make a barricade across the doorway. As he worked, he gripped his sons by the neck in quick affection, then sent them scurrying into Ogedai's sleeping chamber to gather anything they could lift. He saw Torogene murmuring to them and they relaxed as she directed them. Both young men were used to their mother's commands and Torogene was a large woman, motherly and brisk in her manner.

There was another small lamp there. Torogene handed it out to Sorhatani, who placed it so that some of its light reached Tsubodai. It made huge shadows in the rooms, great dark figures that leapt and danced, dwarfing them all.

They worked in grim concentration. Tsubodai and Huran knew they would have just moments to retreat when the outer door gave way. The couch braced against it would be no more than a nuisance to the attackers as they poured in. Behind them, Sorhatani and Tolui built their barricade without speaking, jittery from fear and lack of sleep. The boys brought them wood panelling, bedclothes, even a heavy pedestal that had to be dragged over the floor, leaving a long scar. It would not hold against determined men. Even young Kublai understood that, or saw it in his parents' bleak expressions. When their pitiful collection of debris was in place, they stood behind it with Ogedai and Torogene, panting and waiting.

Sorhatani rested one hand on Kublai's shoulder, holding Tsubodai's long knife in the other. She wished desperately for more light, terrified of being killed in the gloom, overwhelmed by struggling, bloody bodies. She could not consider losing Kublai and Mongke. It was as if she stood on the edge of a high cliff and to look at them was to step off and drop. She heard Tolui's long, slow breaths and copied him, breathing through her nose. It helped a little, in the dark, as the outer door cracked suddenly down its length and the men outside grunted and howled in anticipation.

Tsubodai and Huran were both wary of the archer on the other side of the door. Each man had to judge when the blows against the rapidly splintering wood would obstruct the hidden man, then strike a blow into the faces in the dark. The attackers were pressing, knowing they were near to getting in at last. More than one fell back with a cry from a sword blade, licking out like a fang and withdrawing before the archer could see through his own people. Someone out there was dying noisily and Huran was panting. He was in awe of the ice general fighting at his side. Tsubodai could have been at a training bout for all the emotion his face showed.

Yet they could not hold the door. Both men tensed as a low panel broke into splinters. Half the door remained, cracked and loose. Crouching men came struggling under the locking bar and both Huran and Tsubodai stood their ground, plunging their blades into exposed necks. Blood splashed them both as they refused to yield, though the archer had moved and sent a shaft that spun Huran around, winding him.

He knew his ribs had broken. Every breath was agony, as if his lungs inflated against a shard of glass, but he could not even check the wound to see if his armour had saved him. More men were kicking at the bar, loosening its bolts in the wall. When that finally gave way, the two warriors would be swallowed in the flood.

Huran gasped hoarsely as he continued to strike out, seeking bare necks and arms beyond the hole. He saw blades jabbing at him and felt blows on his shoulders and legs. He could taste iron bitterness in his mouth and his arms seemed slower as he swung and swung, each breath burning him with its sweetness and heat.