'In the name of Jesu the Christ, who is the living Son of God, I abjure you unclean spirit, and demand that you come out of this woman.'

The woman, poor wretch, was instantly beset with violent tremors, convulsions that seized every part of her body, flinging her back against the straw bed again and again, despite the brothers' best efforts. At the same time, the hideous laughter came forth, bubbling up from her throat as from a very great distance.

'JES-S-S-S-U-U-U!' she hissed with wicked glee, and uttered an unspeakable oath against that sacred name.

The monks fell back in horror. But Charis did not so much as cringe. She held out the cross in her hand. 'Silence!' she commanded. 'You will not blaspheme the holy name!'

The spirit twisted the woman's face in a ghastly grin. 'Oh, oh, please, be not angry with me,' the thing whined. 'Please, fine lady, be not angry with me.'

'In the name of Jesu, I command you to silence!' Charis insisted.

The woman convulsed, her stomach swelled and foul gas broke from her bowels. She spat, and her spittle ran yellow with puss. She laughed and spread her discoloured legs, breaking her foul wind.

Abbot Elfodd appeared, crossed himself and entered the room. 'Brother Birinus told me to come straight away,' he whispered, coming to stand beside Charis. 'What is to be done?'

'I have commanded it to silence,' Charis replied. 'But it is a stubborn thing. Exorcizing it will be difficult.'

'I will do it, sister,' Elfodd offered.

'No,' Charis smiled and gripped his hand, 'I have begun; I will finish. She is in my care.'

'Very well. But I will stand with you.' He nodded to the monks, who took up places across the room; they knelt and began singing a prayer.

The woman lay still, panting like a winded dog. At the sight of the abbot her eyes grew round, she shrieked and spat more of the vile poison. Her hands became claws and she reached for him to scratch him – all the while mouthing silent obscenities.

Charis knelt down, holding the cross before her. I marvelled at her composure: she was so calm, so self-assured. 'Uisna,' she said softly. 'I am going to help you now.' She smiled gently, a smile of such hope and beauty, I believe the smile alone could have healed any malady. 'Rejoice! It is God's good pleasure to heal you today, daughter.'

Poor Uisna's eyes rolled up into her head and she spewed forth more puss and bile, and began choking on it.

The abbot bent over her and lifted her head. Her arm whipped up and struck Elfodd on the side of the face with such a blow that he was flung back against the wall. The monks prayed louder.

'I am unharmed,' said Elfodd; rubbing his jaw, he returned to his place. 'Continue.'

'In the name of the Most High God, Lord and Creator of all that is, seen and unseen, and in the name of his Holy Son, Jesu, Beloved Friend and Saviour of men, I renounce you, Evil One. I command you to come out of this woman and trouble her no more.' Charis held the cross before the woman's face; Uisna shrank from it, expressions of terror and triumph rippling over her features.

'In the name of the Christ, be gone!' Charis shouted.

At once, the woman gave out a tortured scream. It seemed as if the sunlight dimmed and the room became cold, and that a rushing wind filled the room. This unseen wind whirled once, twice, again; then, lifting the thatch of the roof, raced out into the clear blue sky above.

Uisna lay as one dead: limp, grey-faced, no breath left in her body. But Charis placed the wooden cross on her breast and, taking the woman's discoloured hands in her own, began rubbing them gently. Abbot Elfodd lifted the vial of oil, offered a blessing, and, dipping his finger, anointed Uisna's head.

Both Charis and Elfodd prayed over the woman then, asking Jesu to forgive her sins, and heal her body and soul, and receive her into the Holy Kingdom. It was simply done and, when they finished, Elfodd said, 'Awake, dear sister, you have been healed.'

Uisna's eyes fluttered open. She looked up at the two bending over her, puzzled. 'Am I..? What has happened?'

'You have been saved,' Abbot Elfodd replied. 'And you have been healed.'

Uisna sat up slowly. She raised her hands, and her mouth fell open in awe. The grotesque bruises had vanished, and her flesh was smooth and white. She lifted the hem of her mantle: her feet and legs were no longer discoloured; the flesh was firm and healthy, the once-broken leg straight.

'Oh!… Oh!… ' Uisna cried, throwing her arms around Charis. Tears streamed down her face.

The monks exclaimed in praises to God. Abbot Elfodd embraced the woman and, as if it could no longer remain silent, the bell at the Shrine began ringing out wildly. Moments later monks began crowding into the room to share in the joy of the miracle.

'You must continue in faith, sister,' warned Elfodd gently. 'Renounce sin, Uisna, take Jesu for your Saviour, and trust only in him. Be filled with God and his Holy Spirit so that the evil spirit cannot return again – or it surely will return sevenfold.'

And I – suddenly, I felt as if the room was closing in around me, suffocating me. I could not stand to be there any longer. With the sound of thanksgiving and praise songs ringing in my ears, I fled the place, my breath coming in raking gasps.

Charis found me later, where I sat among the reeds below the Tor with my feet in the water. The sun was lowering in the afternoon sky and she came to me and quietly sat down beside me on the bank, laying a hand on my shoulder.

'I saw you run from the sickroom,' she said softly.

I shook my head sorrowfully. 'I am sorry, Mother, but I could not stay any longer – I had to get away from there.'

'What is wrong, my Hawk?'

I turned to peer at her through a mist of tears. 'I have been afraid,' I sobbed, tears running freely now. 'I have been afraid… and oh, oh Mother, I have failed… I have failed… '

Tenderly, Charis gathered me into her arms. She held me for a long time, rocking slowly, gently. 'Tell me, my son, how have you failed?' she said at last.

'There was so much,' I answered finally, 'so much I meant to do. And I have done nothing. I have betrayed the trust of my birthright. I have strayed; I have wandered far, Mother; and I have wasted myself in empty pursuits – because I was afraid.'

'What did you fear?'

I could scarcely bring myself to say the word. But, squeezing my eyes shut, I forced it out: 'Morgian.'

Charis said nothing for a long time. She was quiet so long, I turned to look at her and saw that her eyes were closed, shedding silent tears beneath her lashes.

'Mother?'

She smiled bravely. 'I had thought myself free of her. Now I know I never will be. But her power belongs only to this world.'

'I know that – at least I was reminded of it today… that poor woman – '

'Uisna is healed, Merlin. God has made her whole.'

'Are there many like her?'

'Yes,' Charis sighed, gazing across the lake to the Tor, 'and more all the time. She is the third since winter. Abbot Elfodd tells me that it is the same in other places. He has spoken to the bishop about it – there is talk of a plague.' I winced. 'A plague of evil spirits?'

'Bishop Teilo says that it is to be expected. For when God's kingdom increases, Satan is roused to wrath. The Evil One seeks always to keep us from the knowledge of God, for then we are defenceless before him.' She smiled again. 'But, as you have seen today, we are far from defenceless.'

I remembered that day on the mountain-top in Celyddon, and I shuddered. A plague of evil spirits – a ghastly thought. Yet, it was true, our Lord was more powerful in his simple goodness than the Enemy in all his vast evil.

That is what I had seen this day at the Shrine, and I had been admonished – indeed, I had been rebuked – and sternly reminded that I feared for nothing. Morgian could be faced, and Morgian could be defeated. This truth, like so many, was bitter to me, for it brought me to my knees beneath the weight of all my failings.