Whenever Publius Sextius had had the opportunity to speak with him, he’d been impressed by the expression in Caesar’s eyes and by the sense of determination and command that emanated from him. A predator, yes, but not bloodthirsty. He was quite sure that Caesar felt repugnance at the sight of blood.

How often he had marched at his side, watching as the commander rode by, as he spoke with his officers and with his soldiers. When Caesar recognized someone who had distinguished himself on a day of pitched battle, he would always get off his horse to talk with him, make a joke or two. But his most vivid memory of Caesar went back to the night after the battle against the Nervii, after he, Publius Sextius, commander of the Twelfth, had returned to camp on a stretcher, a bloody mess, more dead than alive, but victorious. He had seized the standard that day and carried it forward towards the enemy himself. He had regrouped the fighting units, instilling courage into his men, and had been the first to set an example.

Caesar had come to visit him, alone, in the tent where the surgeons were trying to stitch him up by the dim light of a few tallow lamps. Leaning close, Caesar had said:

‘Publius Sextius.’

The centurion could barely form a word but he recognized his commander.

‘You saved your comrades today. Thousands of them would have been massacred and years of work would have been lost in a single moment. You saved me, too, along with the honour of the republic, the people and the Senate. There’s no reward that equals such an act, but if it means anything to you, you should know that you will always be the man I rely on, even if everyone else abandons me.’

Then he’d lowered his gaze to look at the centurion’s body, covered with cuts and gashes.

‘So many wounds,’ he whispered with dismay in his voice, ‘so many wounds. .’

Publius Sextius wondered why, in this moment of total solitude, in the middle of a night-long journey through the deserted forests of the Apennines, with a snowstorm raging all around, he should remember those words.

In front of him, the inscrutable Sura plodded on at a steady pace, holding the torch high, staining the immaculate snow with its ruddy reflection, leaving behind him the prints of a good, strong, patient horse who continued, one step after another, further and further up the twisting path, under the skeletal branches of the beeches and oaks.

It occurred to Publius Sextius that someone might have gone ahead and be setting a trap. Maybe Sura was leading him into an ambush from which he wouldn’t escape. Maybe the message would never arrive at its destination in time. But then he remembered how the innkeeper had insisted that he spend the night in the mansio, safe inside under the watchful eye of four legionaries, including Baebius Carbo of the Thirteenth. No one knew where dawn would find him tomorrow.

Sura lit the second torch and threw the first stub into the snow. It glowed for an instant, then died in the darkness of the night. A bird surprised by the sudden light of the torch took to the sky with a shriek that sounded like despair before disappearing far away in the valley.

The wind died down. There wasn’t a sound now, or traces of life of any sort. Even the rare milestones along the road were buried in the snowdrifts. All Publius Sextius could hear were Caesar’s words, repeated endlessly in his lonely, empty mind: ‘So many wounds. . so many wounds.’

In Monte Appennino, per flumen secretum, a.d. VI Id. Mart., secunda vigilia

The Apennine Mountains, the secret river, 10 March, second guard shift, ten p.m.

Mustela floundered helplessly in the swirling waters of the underground torrent, dragged along by the current. The whirlpools would suck him under the surface, where he tried to hold his breath for as long as he could in a struggle to survive until he was tossed up further along, where he would spit out the water he’d swallowed, gulp at the air and then disappear under the waves again.

He stifled his cries when the current smashed him against the rocks and he could feel blood oozing from his cuts. More than once he thought he would lose his senses as he hit his head hard or took such a pounding from the waves that he didn t think he would survive.

Suddenly he felt something grazing his belly. Gravel and sand. He grabbed at an outcrop of rock and managed to stop and to catch his breath as he lay in a small bend of the river where the water was shallow.

Panting uncontrollably, he tried to work out whether he had any broken bones and to ascertain what was pouring from his side. He touched his hand to his mouth and could tell from the sweetish metallic taste that it was blood. He stuck his fingertips into the wound and discovered that the skin was torn from his hip to his ribcage on the left side. However, the gash had not penetrated too deep and so he hoped that no serious damage had been done.

He could hear the sounds of the waterfall he’d already gone through coming from upstream. Further downstream there was a different noise, deeper and gurgling, but the utter darkness filled him with an anxious uncertainty verging on panic. He had no idea where he was, how far he had come and how much further he had to go. He’d lost all sense of time since the moment when he’d lowered himself into the icy river and let go of the last handhold along the water’s edge.

His teeth were chattering and his limbs were completely numb. His feet hung like dead weights and jolts of pain shot up from his side and one of his shoulders. He backed into a craggy area that turned out to be a small, dry cave. It was warmer there and big enough for him to crouch in. He even managed to stop the bleeding by tying a strip of fabric ripped from his clothing around the wound as a bandage. He let himself fall back and drowsed, more out of exhaustion than any desire to sleep. When he came to, he couldn’t have said how long he’d been there, but he knew that he had to continue his journey through the bowels of the mountain. He invoked the gods of Hades, promising to make a generous sacrifice if he managed to get out of their underground realm alive. Then he dragged himself back towards the water, lowered himself into the freezing river and let the current carry him away.

For a long time he was tossed around, battered, knocked under and thrown back up, as if he were in the throat of a monster, a sensation that felt more real to his terrified mind than being in the river.

Then, little by little, the speed of the current began to lessen and the channel became wider and less precipitous. Even the crashing noise of the waves died away. Perhaps the worst was past, but he couldn’t be sure. He had no way of knowing what new dangers the river might have in store for him.

But he was so exhausted from the cold, his endless struggle and his constant gagging as he coughed up the water he had swallowed that he merely let himself go, abandoning himself like a man would to death. A long time passed, how long he couldn’t tell.

The darkness had been so enveloping and so dense until then that he couldn’t believe it when the faintest glimmer of light came into view in the distance. Could he have reached the end? Would he see the world of the living again? Hope instilled a surge of energy and he dived into the middle of the river and began swimming. The vault of the tunnel within which the water flowed seemed to lighten imperceptibly, so that he was no longer in pitch blackness. This was the promise of light more than light itself, but with the passage of time it grew stronger until he became aware of the pale glow of the moon brightening the night sky.

Utterly exhausted by the enormous strain on his body and frozen half to death, Mustela fell to the ground, finally outside, finally under the vault of the sky, on a low, sandy bank. He laboriously dragged himself towards dry land and collapsed, without a single drop of strength left in his body.