They rode on, the soft impact of the horses’ hooves providing the only sound amid the desolate landscape surrounding them. At the end of the wadi the tracks bent to the left and headed across a wide open stretch of sand, broken up by a handful of dunes, towards another rock formation two or three miles away. It was late in the afternoon and already long dark shadows stretched across sections of the desert. Halfway across this expanse Symeon halted them at the base of a dune and dismounted.

‘I’m going to have a look from the top. See if I can see any sign of him.’

‘I’m coming too,’ Cato decided and jumped down.

‘There’s no need.’

‘I’m worried about Yusef. I have to see for myself.’

Symeon shrugged and started to climb the side of the dune.

Cato turned to Macro. ‘Won’t be long.’

Macro reached for his canteen and took a small swig. ‘If you see any sign of water, let me know.’

Cato smiled, then moved off, following Symeon’s tracks up the dune. As soon as the slope made itself apparent the going became difficult as the sand shifted downhill under his feet, to such an extent that it felt as if he was making no progress at all. But eventually, exhausted, he flopped down beside Symeon and scanned the way ahead. On the far side of the dune the sand continued for another mile before it reached the rock formation. Now Cato could see that there was a cleft in the rocks that ran from top to bottom. At the base of the cliffs was a small clump of shrubs and a handful of stunted trees.

‘There’s water there.’

‘That’s not all.’ Symeon strained his eyes. ‘Look again.’

This time Cato saw it, the tiny shapes of two horses, almost lost against the shrubs, and the figure of a man, or a boy, sitting in the shade of one of the trees.

‘I can only see one of them.’

‘Calm yourself, Cato. We’ve seen no sign of a body since we’ve been following him. No body, no blood. I’m sure Yusef is over there with him.’

Cato wanted to believe it. ‘All right then, what shall we do?’

‘We have to wait. If we approach him now he’ll be sure to see our dust the moment we emerge from behind this dune. So we wait until dark, and then ride in.We can stop some distance before the rocks and continue on foot. If we can surprise Bannus then we might be able to grab Yusef before he can do anything.’

‘Right.’ Cato nodded. ‘That’s the plan then.’