If this went wrong, could they fight their way out? They would be outnumbered three to one. Yet the garrison would not be prepared, and the majority would be unarmoured. Narses had said there were also half a dozen torturers, and twice that number of servants. But they should be of little account, no more than the whores. Under their long robes, the Romans were wearing all their equipment. Their bows and quivers were on their belts. Should they seize the moment, and try and take the place by force of arms?

No, that was the course of last resort. Even if they prevailed, with those odds, there was no way they could prevent some of those in the castle getting away. Once the survivors were down from the mountains, they would raise all the troops in Hyrkania, and the whole of the countryside, against them. The garrisons along the Walls of Alexander barring the Steppe would be alerted. There would be no way out.

Narses greeted the warden affably, as one Persian noble to another.

The two men talked at length. The warden appeared put out, perhaps suspicious. Narses was conciliatory, but firm. Both frequently looked at the men around the wagon.

It had been decided that they would not attempt to hide their origins. Despite their loose eastern robes, the westerners did not look Persian. Valens and Decimus could only manage a few words of the language. Narses would be telling the warden that the men he commanded were Roman soldiers captured with the Emperor Valerian. They had volunteered to serve in the armies of the King of Kings, given their oath to Shapur. Such things were not unknown. Narses had led them to Hyrkania from distant Bactria, where they had been stationed previously. It was best to keep such men well away from the Roman frontiers, where they might be tempted to desert. They had been assigned to the supply wagon because the journey to the Castle of Silence was an unpopular duty with the Persian soldiers.

Everything hinged on Naduk believing the story, and the zendanig of the state prison was not going to be by nature a trusting man. So far he did not appear convinced.

The warden marched past Narses towards the wagon. All the soldiers bowed slightly from the waist, put the fingers of their right hand to their lips, and blew a kiss: the ritual proskynesis due to a Persian of superior rank. Valens’s heart sank as the zendanig halted in front of him. Naduk was a head taller than him, and as broad as an ox.

The warden barked something in Persian.

Valens smiled apologetically. ‘Persian not good yet.’

Naduk looked down at him with contempt, then spoke rapidly over his shoulder to Narses. Valens kept his eyes respectfully down as Narses replied.

‘To arms!’ Naduk roared.

It was one of the handful of phrases of Persian Valens knew.