Trembling with cold and nervous exhaustion, Marcus edged round a bend in the gorge and saw a sliver of starlight a short distance ahead, revealing the exit. Then he stopped. It was obvious that Brixus would have sentries at either end of the narrow passage, and those on the outside were likely to be far more vigilant. However, they would be looking for threats approaching the entrance, so would be facing the other way. All the same, Marcus slowed his pace and hugged the side of the gorge as he felt his way towards the opening. Beyond lay a small clearing surrounded by pine trees and covered in a thick blanket of snow. A path crossed the clearing, the snow trodden down by the passage of many men and horses. Marcus was steeling himself to emerge from the gorge and make for the pines when he saw movement along the treeline.

A small party of men was trotting up the path towards the mouth of the gorge. They were halfway across the clearing when a score of men burst from the trees on either side, spears levelled as they closed round the new arrivals.

‘Who goes there?’ a voice called out menacingly.

The men on the track stopped dead and their leader raised an arm as he responded. ‘Trebonius of the scouts. Let us pass."

‘Trebonius? You weren’t expected for days. You’re supposed to be keeping watch on Caesar.’

‘We have been. He’s marching this way. Now let me pass. I have to inform Brixus!’

‘Caesar’s coming …’

Marcus felt a mix of hope and anxiety as he heard the news. If his plan was to succeed he must find Caesar as soon as possible, while there was still a chance to prevent a bloodbath. The men in the clearing were talking in low urgent tones that Marcus could no longer make out. But for a brief moment their attention was on each other. Taking a deep breath, Marcus crouched down and moved slowly out of the mouth of the gorge, staying close to the cliff as he made for the trees. It was only a short distance, no more than twenty paces, and he reached the nearest of the pines as the scout party continued towards the camp. The sentries turned and headed back to their stations. Marcus ducked under a heavily laden bough and heaved a sigh of relief as the clearing disappeared from sight. Then the sleeve of his tunic caught on the stump of a broken branch and the whole bough jerked, dislodging a small avalanche of snow.

‘Over there!’ a voice cried out. ‘There’s someone over there! Under that tree. Hey, you, stop!’

Marcus cursed himself for a clumsy fool, but was already in motion, scurrying under the low branches as he scrambled deeper into the trees. As branches swished past him he heard shouting behind, and the crack of twigs as his pursuers plunged into the forest.

‘Don’t let the spy escape!’ a voice ordered. ‘Kill him if you have to!’

Marcus stayed low and ran on, swerving round the tree trunks, barely able to make out the way ahead. He had no idea which direction to head in but kept running, steering away from the sounds of his pursuers. But he knew he was close to exhaustion. Perhaps it would be better to stop, press himself against a tree trunk and keep still while the men passed by. Then he could double back to escape in a different direction. Even as the thought raced through his mind, he knew he dare not risk being caught and killed on the spot, or taken back to Brixus. The veteran gladiator would not forgive his escape attempt. Though Brixus had been a close companion of Spartacus, his first loyalty was clearly to his fanatical hatred of Rome. There would be no mercy shown to anyone who betrayed that cause, not even the son of Spartacus.

That thought gave him an extra burst of energy and Marcus forced himself on, stumbling through the dark forest as the ground beneath his boots began to slope gently down. Behind him, the rebels called to each other as they kept up the chase.

After about a mile the trees abruptly began to thin out and he was suddenly in the open, on the edge of an expanse of uneven ground. A large stone enclosure stood at the bottom of the slope where the trees began again, a few hundred paces away, and Marcus guessed that must be a summer pasture for goats or sheep. If he continued down the slope, his dark cloak would stand out against the snow and he would be spotted the instant the rebels emerged from the forest. With a rising sense of panic, he turned back to re-enter the trees when a voice called out close at hand.

‘Over here! Some tracks … He’s been this way!’

A cold wave of terror raced down his spine. There was only one direction now and Marcus spun round and ran for his life. He had covered no more than thirty paces across the smooth sweep of snowy field when the first of the pursuers burst out of the forest.

‘There he is! Just a kid!’

‘Get him!’ another voice called. ‘He mustn’t get away!’

Marcus risked a quick glance over his shoulder and saw several dark figures converging on him from the treeline, kicking up sprays of snow as they raced down the slope. He sprinted on, heart pounding, fear causing his stomach and chest to tighten so that he panted raggedly. When he looked back again they were much closer, their longer stride gaining on him. They were halfway across the field before Marcus realized he could not reach the shelter of the trees before they caught up. He felt the energy draining from his legs and there was nothing he could do.

In front of him lay the stone wall of the pen and he saw the sudden movement of a dark shape rising above it. Then another, and another.

‘Heads up, lads! We’ve got company.’

Marcus slowed momentarily, unsure if these were more of Brixus’s men. Then the shouts behind caused him to grit his teeth and run on.

‘Kill him!’ a voice cried out. ‘He mustn’t give us away! Kill him!’

Something dark flew close by Marcus’s head and exploded into the snow. He saw the shaft of a spear as he ran by and any moment expected to feel the piercing blow as the next missile punched through his back and tore through his body. A short distance ahead, one of the men inside the stone wall reared up and drew his arm back.

‘Get down, lad!’ he shouted hoarsely. ‘Down!’

With no time to think, Marcus hurled himself forward into the biting cold of the snow, rolling over towards the wall. He did not see what happened next, only heard the thud and deep grunt from close behind him. Scrambling on hands and knees, he glanced back and saw one of the rebels collapse to the ground, a spear shaft protruding from his stomach.

‘Get stuck in!’ a voice roared from behind the stone wall and dark shapes clambered over, short swords in hand. Some carried large oval shields as they charged towards the rebels, shouting their battle cry. Swords clattered all around Marcus. With nothing to protect himself, he crouched low as he ran to the wall and clambered over the rough stones before dropping inside.

He landed heavily, forcing the breath from his lungs, and it was a moment before he took in his surroundings. The interior of the pen was filled with legionary marching yokes, and bundles of javelins leaned against the wall. A handful of men were still there, too late to take part in the skirmish outside. Marcus rose to his feet, gasping, and peered over the wall. The fight was already over. Most of the rebels had turned to flee, racing back up the slope towards the cover of the distant trees. Several bodies lay in the snow, some of them writhing and groaning with pain. The soldiers stood jeering, waving their fists and swords after the rebels.

‘Right!’ a voice called out over the shouts. ‘You’ve had your fun, lads. Get the wounded into the pen. Now then, where’s that boy? I want a word with him.’

A tall, powerfully built man climbed over the wall and looked to either side before he caught sight of Marcus’s slight form and strode over. He stood, hands on hips, and stared down at him.