At another turn of the path Castus paused, sucking down great lungfuls of air. His head was reeling. ‘What happened to Sallustius?’ he said, gasping the words. ‘Was he wounded or dead?’
‘He fell…’ Victor said, coming up behind him. ‘I don’t know if he was hit. He said to run and… and I ran. I’m sorry…’ The shame was in his voice. Shame and fear.
‘No time for that now.’ Brinno had clambered up the next incline and was waving down to them; Castus could just make out his gesture against the sky.
Up the last twist of the path, the trees fell away and they stood on an open summit with the aqueduct stretching across the valley before them, massive and pale, as if it were made of moonlight. Castus had not realised they had climbed so far. The slope rose again ahead of them, but it was thick forest now, holm oak and thorns, impassable. He could not see where the path had gone.
‘We need to cross there,’ Brinno said, pointing at the aqueduct. Along the crest of the uppermost tier of arches, above the water channel, there was a narrow walkway of flat stone slabs. Castus looked at it: a thin grey ribbon stretching across a vast gulf of air. He felt his heart clench in his chest.
‘No,’ he said.
But Brinno was already pushing his way between the dry bushes towards the end of the aqueduct.
‘Come on – if we get across there we’re on the far ridge! We’ll be well ahead of them…’
‘No,’ Castus said again. ‘I’m not going across that.’ But Victor was coming up the path behind him; he needed to follow Brinno or move aside. Trying to swallow down the tightness in his throat, Castus moved off after Brinno, down into the hollow where the upper arches and water channel of the aqueduct met the hillside. His calf muscles were burning, but a wild dizzying fear was rising in him.
‘I can’t do it,’ he called. ‘I don’t like heights.’
‘It’s nothing,’ Brinno called back. ‘Look – it’s ten feet across on the top. We can run over it easily! Just don’t look down…’
Now they were in the hollow, and Castus saw the huge masonry of the aqueduct rising out of the scrub and grass. The big rough stone blocks looked reassuringly solid – it was only when he glanced to his left and saw that stone walkway stretching out like a tightrope into the night that his blood froze.
Brinno had already clambered up onto the top of the water channel. He reached down and heaved Castus after him, and Victor scrambled up behind them.
‘Now,’ Brinno said. ‘We run.’
He set off at once, jogging easily along the walkway with his cloak pulled up around his left arm. Castus started after him; only a few paces, and the trees fell away to either side. He stepped out into the sky.
There was a breeze coming across the high ridges and he felt it at once pushing at him. Fixing his gaze on Brinno’s receding figure, he concentrated on putting one foot in front of the other, keeping moving. He thought of Victor coming across behind him; he could not stop or slow down now. But the stone path along the crest of the aqueduct, which had looked so straight and level, seemed to have a subtle curve and chamfer: every few steps Castus found himself veering towards one side or the other, his breath getting tighter and tighter.
He glanced desperately to his left, and saw the gulf yawning beneath him. The drop must be close to two hundred feet. He could just make out the thin vein of the river in the moonlight far below him. Then a bolt of stark terror went through him so fierce his legs almost buckled. Something whirled close to his head and he flinched: it was just a dry leaf carried on the breeze, but he ducked to let it blow past him and then found he could not straighten up.
Forcing himself onward in a half-crouch, he moved out onto the central span of the aqueduct. Behind him he could hear the shouts of the pursuers as they boiled up out of the forest. The drop to either side of the stone walkway seemed all-consuming; Castus felt it sucking him over the brink. Again and again he had to close his eyes, then open them again as his senses whirled, convinced that he had slipped off the path and was falling through the empty black air. Again and again he found himself still perched on the veering ledge, precariously balanced above the emptiness.
May the gods get me out of this, he prayed. Sol Invictus, light against evil, guide in darkness… Jupiter, lord of thunder and rain, Isis, Queen of Heaven, I vow sacrifice to you… carry me safely from this place…
When he looked up he saw the walkway open before him: Brinno had already reached the far end and vanished into the dark trees. Glancing back, Castus saw Victor standing alone with his sword in his hand, facing back towards the valley slope and the pursuing men.
‘Victor!’ he managed to shout. ‘Don’t stop! Keep moving!’
‘No – you go!’ the young man called back. He looked firm and steady, his head high. ‘You go and I’ll hold them here – they won’t get past me!’
‘That’s madness – come on! Just move!’
‘No! I shouldn’t have left Sallustius behind – I shouldn’t have tried to save myself. I failed, brother. Now I have to pay my debt!’
Already the first of the pursuers were climbing up onto the far end of the aqueduct, edging out along the stone walkway. Victor stood braced, in a fighting stance, waiting to meet them. Castus knew that there was nothing he could do to save him, short of grabbing him and pulling him away by force. There was only room for one man to fight effectively on the narrow ledge.
This was Victor’s moment, Castus realised. All his training, all his elaborate sword drills, had led to this. The enemy were closing on him now, cautious, weapons ready.
Castus forced himself to turn away and push onwards towards the far slope. He heard Victor’s high scream of a battle cry. Then something else: the clink of metal against stone, and a familiar snipping whine in the air.
Archers. They had archers.
Even as the yell left his throat he saw the young man jolt and stagger, clutching at the arrow in his hip. As Castus watched, Victor’s leg gave beneath him. He flung his sword wildly upward, but his balance was gone. Breathless, Castus saw the young man topple sideways. Victor made no sound as he fell, his body seeming to fold and then spin like a leaf as it vanished into the depths of the valley.
‘Don’t shoot! Idiots! Don’t shoot – take them alive!’
It was Flaccianus shouting. Castus had dropped to lie face down on the walkway. The stone still felt warm beneath him from the heat of the day’s sun. Raising his head, he could see the men beginning to edge out once more along the aqueduct, coming slowly but surely towards him.
Had Brinno got clear by now? At least that would be a victory. If Brinno could carry word of what had happened to the north, to Constantine, their enemies would pay with their lives. Nigrinus would die. But Brinno needed time.
Castus could taste blood in his mouth. As he raised himself to kneel, and then to stand, he felt a new strength in his limbs. The drop to either side no longer dragged at him, no longer sucked his courage or his nerve. He took two steps forward, braced his legs and drew his sword.
‘Come on then!’ he cried. ‘Come on, you goat-fuckers!’
His opponents slowed as they approached, bunching together on the narrow walkway. Castus recognised the man in the lead: one of the agents who had accompanied them from Arelate, a man named Delphius. His face was a blanched mask of terror. Behind him were two others armed with spears.