They retreated from the brow of the ridge, keeping low, and hurried back down to the camp to rejoin the others and report what they’d seen. Aziz and Father Bugnolio took the news grimly, but Ramin was ready to panic. ‘We can’t stay here,’ he moaned frantic with agitation. ‘They’ll slaughter us all.’

‘We’re going,’ Madison said in a tight voice. ‘But there’s something I need to do first.’

‘You’d better make it damn quick, lady, whatever it is,’ Holt said, looking at his watch. The sound of the approaching convoy was clearly audible now over the roar of the wind. The first splashes of cold rain began to spatter the rocks. Baldacci, Liebowitz and Nielsen were already at work loading their kit back into the vehicles while the others pulled down the makeshift tarp shelter and set about erasing all trace of the camp, as best they could. Madison looked again at Ben, anxiety in her eyes too. He knew her too well to think she was overly worried about her own safety. It was her companions she was concerned about. And something else, too.

‘Will you help me?’ she asked. ‘Over here.’

Before Ben could answer, she took off at a sprint towards the ruins. He followed her as she ran ahead of him in the darkness. The rain was falling harder now, driven by the wind that had risen to a howl. He lost sight of her for a moment, looking about him in confusion; then there she was, crouching among the rubble beside a row of worn, uneven stone blocks that he realised was the edge of the large rectangular slab she’d talked about earlier, the foundation of the ruined building where her father had made his discovery. As he hurried over to her, he saw the long fissure in the stone slab, just wide enough for a person of light build to squeeze through, and the two coils of rope on the ground next to her. Her hair was soaked and falling into her eyes. She brushed it away and busily set about tying the end of one of the ropes around her slender waist, knotting it tight.

‘Madison,’ he protested over the noise of the wind, ‘we don’t have time for this.’

‘Then shut up and help me,’ she said. ‘We can’t let those sons of bitches have it.’

‘Have what?’

‘Remember you said, “there’s nothing here” and I told you “not quite nothing”?’

‘Yes, and I didn’t know what you were talking about then either.’