They went down to join the others. Valens told Aulus to take some food, and go up to keep watch. The rest he ordered to see to the horses – including the mounts of Aulus, the boy and the eunuch, as well as the spares – and then gather to eat a cold meal. While they chewed hard tack and bacon, he briefed them on what had been seen. He spoke in Latin to avoid alarming Prince Sasan and Barbad. When he had finished, Iudex went off to one side to pray. Today, Iudex scooped some water from the stream into his mess tin, and then sat cross-legged, staring at its surface, seemingly lost in meditation. The rest remained sitting in a circle. The anxiety was evident on every soldier’s face.

It was Decimus who voiced their concern. ‘It looks like they are expecting us.’

‘There has been no time for a rider to get down from the Castle of Silence.’ Valens hoped the words sounded more confident than he felt.

‘Then they already knew we were coming,’ Decimus said.

‘If they did, I know who told them,’ Clemens spoke as weightily as a senator in the Curia.

Everyone looked at Clemens.

‘Narses here is a Persian,’ Clemens said. ‘They are his kin.’

‘When have I betrayed our brotherhood?’ Narses spoke with quiet anger.

‘You made sure you did not kill any of your own at the supply convoy.’

Narses looked disconcerted.

‘And now you are leading us straight to the Persian troops on the Walls of Alexander, promising us some cunning way of getting through the defences that you will not tell us.’

Narses rallied. ‘I am no traitor. Put me to the test. Place a hot iron on my tongue, have me drink sulphur, pour molten metal on my chest; if I do not lie, it will run off me like milk.’

Valens noted that Decimus seemed not to disapprove of this ghastly and divisive procedure.

It was Hairan who put an end to talk of an ordeal. ‘The gods know, as a man of Hatra, no one has more reason to hate the Persians than me. But Narses has faithfully guided us to the Castle of Silence and then out of the mountains. Without him we would have been lost, as helpless as children. If he were a traitor, he could have deserted us at any time. When he returned with Persian warriors, we would have been at their mercy.’

Gravely, Narses put his fingers to his lips, and blew Hairan a kiss.

The handsome young Hatrene bowed in return. ‘Not all Persians are cruel, untrustworthy bastards. Even if they do fuck their own daughters.’

Clemens was not quite finished. ‘Then how exactly are we going to slip through the walls manned by thousands of Sassanid warriors?’

‘We are not.’

‘What?’

Narses told them his plan. They looked at each other, then burst out laughing.