‘God determines everything but the devil provides the means. Fate is inescapable. I do not determine it, I foresee it. The moment will present itself; Blackstone will be weakened. You will seize the moment. Trust me, you will know when that time comes.’

She turned away and walked towards the opening in the rock. De Hayle breathed a sigh of relief and wiped the back of his hand across his dry mouth. He looked at the man still holding the boy’s head. ‘Get rid of it. Put a rock in the barrel and throw it in the river. It mustn’t be found.’ De Hayle knew that if Blackstone discovered the boy’s head he would know they had murdered the old Jew and his rage would be unleashed on him. He watched the woman’s dark cloak merge into the darkness. There was no doubt she had the second sight. She saw the future and she saw into men’s souls. And she had no reason to lie. The fear eased from him. There was comfort to be had in that. He did not know when or where, but he would defeat and kill Thomas Blackstone.

*

Blackstone and Will Longdon reached the base of the well on the final turn of stair.

‘Two hundred feet down, Thomas, I reckon.’

‘Not far from it. I don’t hear the voices now.’

‘No. But whoever it was needed to be down here.’

Blackstone watched the lantern flame waver and turned his face to the incoming air. ‘Or out there.’ He walked along the flat rocks bordering the river until he reached the cavern’s opening. There was no sign of anyone. He stepped out.

‘The overhang would obscure anyone.’ He looked around. ‘Back there,’ he said, seeing the sloping pathway beyond where they had reached the base of the well and the river slid away out of sight underground. They found another passage and clambered up the worn incline. Blackstone led the way as the limestone walls twisted left and right, and as they climbed higher they saw steps cut into the rock.

‘What is this? It’s beyond the well,’ said Longdon.

Blackstone looked back at where they had started and then up at the hewn roof and walls. ‘It’s a siege tunnel. At some time in the past an enemy dug their way beneath the castle walls.’ The steps ahead were less curved than those built in a spiral around the well. Eight steps, a turn, a dozen more, a passage, then more climbing higher. Every cut in the stone showed either that the defenders had built a staircase to stop an enemy tunnelling or that those who laid siege had breached the castle’s defences.