I recognized none of the horsemen, and none bore an insignia on their shields. A few of the horsemen had covered their leather shield faces with black pitch, but these men were not Oengus mac Airem’s Blackshields. They were a scarred group of veteran warriors, bearded, ragged-haired and grimly confident. Their leader rode a black horse and had a fine helmet with engraved cheekpieces. He laughed when one of his men unfurled Gwydre’s banner, then he turned and spurred his horse towards me. ‘Lord Derfel,’ he greeted me.

For a few heartbeats I ignored him, looking about the blood-soaked compound in a wild hope that there might still be some means of escape, but we were ringed by the horsemen who waited with spears and swords for the order to kill us. ‘Who are you?’ I asked the man in the decorated helmet.

For answer he simply turned back his cheekpieces. Then smiled at me.

It was not a pleasant smile, but nor was he was a pleasant man. I was staring at Amhar, one of Arthur’s twin sons. ‘Amhar ap Arthur,’ I greeted him, then spat.

‘Prince Amhar,’ he corrected me. Like his brother Loholt, Amhar had ever been bitter about his illegitimate birth and he must now have decided to adopt the title of Prince even though his father was no king. It would have been a pathetic pretension had not Amhar changed so much since my last brief glimpse of him on the slopes of Mynydd Baddon. He looked older and much more formidable. His beard was fuller, a scar had flecked his nose and his breastplate was scored with a dozen spear strikes. Amhar, it seemed to me, had grown up on the battlefields of Armorica, but maturity had not decreased his sullen resentment. ‘I have not forgotten your insults at Mynydd Baddon,’ he told me, ‘and have longed for the day when I could repay them. But my brother, I think, will be even more pleased to see you.’ It had been I who had held Loholt’s arm while Arthur struck off his hand.

‘Where is your brother?’ I asked.

‘With our King.’

‘And your King is who?’ I asked. I knew the answer, but wanted it confirmed.

‘The same as yours, Derfel,’ Amhar said. ‘My dear cousin, Mordred.’ And where else, I thought, would Amhar and Loholt have gone after the defeat at Mynydd Baddon? Like so many other masterless men of Britain they had sought refuge with Mordred, who had welcomed every desperate sword that came to his banner. And how Mordred must have loved having Arthur’s sons on his side!

‘The King lives?’ I asked.

‘He thrives!’ Amhar said. ‘His Queen sent money to Clovis, and Clovis preferred to take her gold than to fight us.’ He smiled and gestured at his men. ‘So here we are, Derfel. Come to finish what we began this morning.’

‘I shall have your soul for what you did to these folk,’ I said, gesturing with Hywelbane at the blood that still lay black in Dun Caric’s yard.