Now the battle begins. I have made the first strike. It is greatly to Morgaws' credit that no one saw it coming. She chose her servant well, and bound him to her with strong enchantments. He is ours, and a more potent weapon would be difficult to find.

Oh, it would have been pure joy to have seen their faces when they discovered the traitor in their midst. I wish I had been there to savour it to the full. But it is not time to reveal myself just yet. I must content myself with the knowledge that my glory will be all the greater for remaining so long undiscovered.

Still, the shock of betrayal is an exquisite pleasure. And that it followed so quickly upon the birth of the Summer Kingdom is especially poignant. Simple treachery, when applied with such swift and thorough proficiency, can be simply devastating. Trust is, I think, the most fragile of the virtues; ever brittle, it shatters easily and, once broken, can never be completely repaired. In a single stroke, I have broken Arthur's most deeply held trusts. There is no force on Earth that can compel a heart to continue trusting when cruel, hard facts fly in the face of faith.

Doubt and fear are ever-faithful allies, I find, and, when joined with suspicion, can become wonderfully debilitating in an enemy. They are like twin hounds baying for blood. Relentless and merciless, they will chase and bite and howl, wearing down the prey until mind and heart and will are spent, and the helpless victim drops from exhaustion.

I do not expect Arthur to surrender easily; nor less yet Myrddin. They will prove stalwart adversaries, I expect. Thus will my eventual triumph taste the sweeter.

And what is this? Morgaws tells me she has come into possession of a certain talisman – a treasure of some kind, by which Arthur and Merlin set great store. An object of power – healing power, apparently, among other things – she used it to bait her trap. She does not tell me what it was, but I suspect the Grail.

That would be a treasure indeed. There were rumours in the wind about this Grail years ago – the miraculous cup of such power, it is able to work wonders of its own accord. Well, these tales are always stirring up the poor folk. Superstition has its uses, I find. Still, I never would have thought Merlin would have anything to do with it; he fancies himself above the common herd and its bovine beliefs.

Dear nephew has surprised me before, however. Therefore, I will make it my affair to find out more about this treasure Morgaws has discovered. In the meantime, I have a little talisman of my own to reveal. Come, enemy mine, the chase awaits you.

'Is this the last one?' wondered Cai, shovelling dry earth onto the body in the grave.

A bright, red-gold dawn had given way to a pale grey monk's-mantle of a sky – a gloomy day to match the mood of death and doom. The dirt was hard-baked and the graves shallow. We worked away in silence, thinking about the horrific events of the previous night. Twelve had been buried, and three more bodies brought from the hillside to the little yard near the lake below the abbey. Cai and I, along with Cador, Bors, and some of the Cymbrogi, had buried our swordbrothers first, before turning to the pilgrims. Many of the dead had families with them, some of whom stood nearby, weeping quietly as their kinsmen were laid to rest.

'One more,' I told him, indicating the last of the three.

Together we dragged the last body to the newly dug grave, and rolled it into the narrow hole. I put my shovel into the mound of dirt and dragged part of the pile onto the body. Cai likewise bent his back to the task, then hesitated. 'God bless him,' he muttered under his breath. 'I know this one.' I glanced up, and he said, 'Is this not the old man who raised the commotion when we closed the shrine?'

I turned and looked into the bloodless face of the corpse in the grave. 'So it is,' I confirmed. The last time I had seen him, he had been striding away with an expression of rapture on his battered old face.

'He said he wanted to see the Grail before he died,' Cai remembered.

Then at least he died happy,' I replied, and began pulling dirt over him.

A moment later, a rider came from the Tor. 'Arthur wants you,' the warrior said. 'Bedwyr has returned. You are to come at once.'

Leaving the mourners to the care of Elfodd's monks, we rode back to the Tor to face the king's wrath. Arthur was standing behind his camp chair – the chair Uther had used as a throne -waiting for us in Avallach's chamber at the Fisher King's palace. Bedwyr and Rhys were standing before the chair, arms folded and unhappy.

'He betrayed us!' Arthur said, his voice the growl of a wounded animal. 'He has betrayed the Summer Kingdom, he has betrayed his king, and he has betrayed Britain.'

'We do not know what happened,' Rhys pointed out.

'Do we not?' demanded the High King, his voice hard and flat and cold. 'Do we not? We know the Grail is gone, and Llenlleawg with it; we know eight Cymbrogi were slain by his hand and fifteen pilgrims as well; we know the Summer Realm lies in ruins; we know he has stolen, murdered, and destroyed. If that were not condemnation enough, he has taken the queen with him – whether by force or by deception, I know not – the queen he has vowed to protect through all things. He shall be hunted down like the treacherous dog that he is, and he shall be killed.'

'Bear,' pleaded Bedwyr, 'be reasonable. We will find him and then we will discover the truth.'

'Let it not be said that Arthur Pendragon was ever less than reasonable,' replied the king icily. 'We shall be a very paragon of reason. If a servant betrays his master, it is reasonable that he should expect to receive punishment. It is reasonable that the murderer should forfeit his life for his crime. It is reasonable to seek justice and demand retribution.'

'Justice, yes, by all means,' agreed Bedwyr. 'But what of mercy?'

'Ah,' said Arthur, 'you think us too harsh. Then let us temper our justice with mercy as you suggest. Know this: the same mercy granted those who were slain shall be granted the one who murdered them.'

Bedwyr glanced at Rhys uneasily. Clearly, they wanted to say more, but, owing to Arthur's poisonous mood, felt their intercessions were only making matters worse. In the strained silence, Cai and I took our places beside our swordbrothers and waited for the storm to break.

'Twenty-three dead! The Grail gone!' the Pendragon roared suddenly, striking the back of the chair with his fist. 'My sword taken, and my queen abducted!' That was the first time I heard that word uttered, but no doubt he was right. The king glared around him, defying anyone to dispute his reading of events. 'Is that not the shape of things?'

No one made bold to answer. Arthur glowered murderously at us; I had never seen him so angry. 'You!' he shouted, pointing at Bedwyr. 'Have you nothing to say?'

'In truth,' intoned Bedwyr wearily, 'I thought we could not fail. We raised the trail at first light, but – '

Arthur cut him off. 'Save me your excuses. You failed.'

'Yes.' Bedwyr shut his mouth and stared ahead.

'A short while ago,' Arthur continued, pacing behind his chair like a caged bear, 'I told Avallach that his worst fears had been realized. He was against enshrining the Grail, but I persuaded him that it would be safe. I pledged my honour to it: The best men of the Dragon Flight will protect it. Nothing will happen to it.' But now – ' He glared at us with true contempt and loathing, and I felt the depth of his anger, restrained now, but dangerously close to flaring. 'Now it has been stolen by one of our own, and we are no closer to recovering it than we were when the alarm roused us from our beds. The blame will fall on me, and rightly so. But, God help me, I will not – '