Kirby jumped up, scowling. ‘I told you back in Cairo. I want nothing to do with it.’

‘I need you to be armed, Kirby. We’re not playing games here. So learn to shoot it, or I’ll shoot you with it.’

Kirby hesitated, narrowing his eyes. ‘You don’t really mean that, do you?’

‘Maybe. Maybe not.’ Ben picked up an empty plastic water bottle and tossed it a few yards away across the sand. He pointed at it. ‘Now shoot that.’

‘I protest at this,’ Kirby muttered as he picked up the little revolver. ‘I really do.’ He screwed up one eye as he raised the gun.

‘The other eye,’ Ben said.

Kirby corrected his aim. ‘How do I know it’s loaded?’ he asked.

‘See the edges of the brass cartridge rims there between the cylinder and the frame? That’s how you know. Then just squeeze the trigger. There’s no hammer, no safety. Just pull. Like I said, an idiot could use it. Which makes it perfect for you.’

Kirby glanced hotly at him, but kept his mouth shut. He aimed the revolver at the water bottle, his tongue protruding in concentration. Then he fired.

The snap of the low-powered.38 was lost in the flat air. The bottle spun as the bullet caught its neck. Kirby jumped back, the gun dangling loose in his hand as though it had stung him. ‘Jesus.’

‘Come on, Kirby. There’s hardly any recoil from that. Four rounds left. Keep going.’

Kirby squeezed the trigger four more times with his finger in his ear. His second and third shots missed the bottle completely. The fourth one clipped it again, and the last one punched a hole right through the middle.

‘Not bad,’ Ben said. ‘At least if Kamal is standing right in front of you and keeps still for long enough, you might get him worried.’

‘I don’t want to hear that,’ Kirby said.

Ben took the revolver from him, flipped out the cylinder and ejected the five empty brass cases. He dropped them in his pocket and loaded five fresh cartridges, snapped it shut and handed it back to him. ‘Keep it with you at all times.’ He patted his right hip, where he had the Jericho hidden in his belt. ‘I’m doing the same.’

‘Kamal could be close, couldn’t he?’ Kirby asked nervously.

‘He could be anywhere.’ Ben turned and headed back towards the vehicle. ‘Go and pick up the bottle,’ he told Kirby. ‘We’re moving on again.’

Chapter Fifty-Two

The sun climbed, and the hellish heat returned. Neither of them had any appetite for food, but Ben made sure they kept themselves nourished with dried fruit and meat to keep up their energy levels. After a few more hours they stopped among the rocks and thorny shrubs to rest and drink in what little shade they could find. The bottled water was lukewarm, but nothing had ever tasted so good. Ben wrapped his Bedouin scarf around his head to keep the sun off, and Kirby imitated his example. Then Ben sat down and spent a few minutes studying the map and making his calculations from the GPS locator on his phone.

‘So, where are we?’ Kirby asked.

‘Cutting southwest, past Lake Nasser and about level with Abu Simbel.’

Abu Simbel,’ Kirby echoed. ‘The great temple of Ramses II.’

Ben nodded. ‘More importantly, it means we’re close to the Sudanese border. Things are going to become more interesting. If we don’t get shot by border patrols, there’ll be rebels out looking to kidnap us. Couple of juicy white men like us are worth a good ransom.’

Kirby paled, but didn’t reply. Ben folded up the map and stood up. There was the faintest breeze, and he pulled back the hem of his headgear to let it ruffle his hair and cool his scalp. He clambered up a sloping flat rock and surveyed the landscape. It was almost Martian in its aridness, and completely empty. He wondered about Kamal. And about Zara. He’d never have let Kirby see it, but he was as close to despair as he’d felt for a long time.

A yell from the Toyota burst his thoughts and made him turn around suddenly. He looked down and saw Kirby bent over in pain with his hand clamped between his knees.

He ran over. ‘What’s wrong?’

Kirby’s face was pale as he showed him his trembling hand. It was bloody.

‘What happened?’

Kirby looked sheepish. ‘I got a thorn.’

‘For God’s sake. Sit down.’

Kirby did as he was told, and Ben inspected his hand. ‘OK, hold tight. This’ll hurt.’ He grasped the end of the thorn, and yanked it out sharply.

Kirby let out a yelp. Ben examined the inch-long thorn to make sure he’d got it all out, then tossed it away, grabbed Kirby’s wrist and had a look at the bloody puncture wound.

Kirby yanked it away. ‘It’ll be fine. I’ll wrap a bit of tissue round it.’

Ben shook his head. ‘Even a trivial wound can get badly infected in this climate.’

‘What are you going to do? I didn’t see you buying any disinfectant.’

‘Yes, you did.’ Ben walked to the Toyota, spent a moment rummaging around in the back, then returned with the jar of honey.

‘You see any hot buttered toast around here?’ Kirby muttered. ‘What use is honey to me?’

Ben unscrewed the lid, dipped a finger in the warm honey and started smearing it over Kirby’s wound. ‘So the professor finally admits that he doesn’t know everything there is to know about ancient Egypt.’

‘Give me a break.’

‘Best antibacterial known to man,’ Ben said. ‘The Egyptians knew it thousands of years before we ever started fucking about with penicillin.’ He screwed the lid back on. ‘Now you can wrap it up with a tissue. And try not to play with thorns again, all right?’

The long, weary trek continued. Sometime in the late afternoon they crossed over the unmarked border and became illegal immigrants into Sudan. No sign of army patrols. No sign of anything except sand and rock and the relentless sun. Another endless stretch of bumping, jolting, creaking drive as they slowly cooked inside the pizza oven of the Toyota. Another freezing night, as they lay listening to the howls of jackals across the rocky valleys.

Then it was another whole day of driving as Ben ploughed doggedly onwards. Whenever they stopped for rest and water he was sitting down with his phone and fine-tuning his calculations. Whereas Wenkaura’s expedition had headed due south and then west, Ben had cut from point A to B directly to form an isosceles triangle. The geometry was hard to pinpoint, but going by the fairly precise co-ordinates from the ancient map, he was sure he was close now. The treasure site was near. He could almost feel it.

But where could it be?

Late in the afternoon they hit a wadi, a dry river bed that had probably remained unchanged since prehistoric times. Its winding path snaked between increasingly high rocky banks that before long had grown up into the walls of a canyon either side of them. There was no turning off. Ben gritted his teeth and kept going.

Up ahead, the canyon path bore around to the right. Ben turned the bend, and braked to a halt.

Kirby had been dozing again. ‘What’s happening?’ he slurred, sensing that they’d stopped.

Ben didn’t reply.

Three hundred yards away up the canyon, a high rocky ridge dominated the skyline. Its top was flat and smooth and silhouetted black against the sky. Cut into the horizon, as symmetrical as the V-notch of a gun rearsight, was a perfect cleft. Ben studied it for a moment, shielded his eyes and looked up at the golden disc of the sun. It was dropping fast as evening drew on, and its line of arc was heading right for the cleft. In a few more minutes, it would be exactly positioned in the V-notch.

It was a stunning, perfect, completely accurate physical representation of the ancient Egyptian hieroglyph for the word ‘horizon’. Now he knew he’d been right that day in Claudel’s study. Wenkaura had meant to convey more than just an abstract symbol.

‘Jesus, Kirby, I think we’ve found something.’