He nodded and then, for a while, he said nothing. Men were singing in the distance and everywhere there were fires. The wounded cried in the dark where dogs and scavengers preyed on the dead and the dying. In the dawn this army would wake drunk to the horror of a field after battle, but for now they sang and gorged themselves on captured ale. ‘At Mai Dun,’ Merlin broke his silence, ‘I came so close. Very close. But I was too weak, Derfel, too weak. I love Arthur too much. Why? He isn’t witty, his conversation can be as tedious as Gawain’s, and he has an absurd devotion to virtue, but I do love him. You, too, as it happens. A weakness, I know. I can enjoy supple men, but I like honest men. I admire simple strength, you see, and at Mai Dun I let that liking weaken me.’

‘Gwydre,’ I said.

He nodded. ‘We should have killed him, but I knew I couldn’t do it. Not Arthur’s son. That was a terrible weakness.’

‘No.’

‘Don’t be absurd!’ he said wearily. ‘What is Gwydre’s life to the Gods? Or to the prospect of restoring Britain? Nothing! But I could not do it. Oh, I had excuses. Caleddin’s scroll is quite plain, it says that “the son of the land’s King” must be sacrificed, and Arthur is no king, but that’s a mere quibble. The rite needed Gwydre’s death and I could not bring myself to do it. It was no trouble killing Gawain, it was even a pleasure stilling that virgin fool’s babble, but not Gwydre, and so the rite went unfinished.’ He was miserable now, hunched and miserable. ‘I failed,’ he added bitterly.

‘And Nimue won’t forgive you?’ I asked hesitantly.

‘Forgive? She doesn’t know the word’s meaning! Forgiveness is a weakness to Nimue! And now she will perform the rites, and she won’t fail, Derfel. If it means killing every mother’s son in Britain, she’ll do it. Put them all in the pot and give it a good stir!’ He half smiled, then shrugged. ‘But now, of course, I’ve made things far more difficult for her. Like the sentimental old fool that I am, I had to help Arthur win this scufHe. I used Gawain to do it and now, I think, she hates me.’

‘Why?’

He raised his eyes to the smoky sky as though appealing to the Gods to grant me some small measure of understanding. ‘Do you think, you fool,’ he asked me, ‘that the corpse of a virgin prince is so readily available? It took me years to pump that halfwit’s head full of nonsense so that he’d be ready for his sacrifice! And what did I do today? I threw Gawain away! Just to help Arthur.’

‘But we won!’

‘Don’t be absurd.’ He glared at me. ‘You won? What is that revolting thing on your shield?’

I turned to look at the shield. ‘The cross.’