'We can leave them,' Merlin told me.

'But – ' I opened my mouth in protest.

'It will be well,' insisted Merlin. 'Leave them.'

I did not like to leave them unattended, but as the house was nearby, and there was no danger, I did as I was bade. Tucking our weapons under my arm, I fell into step behind Nimue as she led the way.

Indeed, the house was not far. I do not see how we could have missed coming upon it, for if we had ridden but a few dozen paces further we would have seen it. Perhaps the pool held our attention, or the willows obscured it…

It was a solid house, built all of stone. A small yard lay before it, clean and carefully tended. To one side was a sheep enclosure, but I saw no sheep within. Inside, the floor was flagged with stone, and the walls were limed. In all it was neat and well-cared-for. Clearly, Nimue and her father lived well and took pride in their small holding.

A fire was burning in the hearth, and there was meat on the spit: three good-sized fowl of some kind. A black pot of porridge bubbled next to the flames. A great table of the son often found in a king's hall occupied much of the single room. An enormous white ox-hide concealed an alcove next to the hearth which served as a bedplace. Another white hide hung across the further part of the room.

Behind this, Nimue disappeared upon entering the house, only to emerge a moment later bearing a wineskin and silver cups on a tray of polished wood.

She poured the wine into the cups and, after dashing a few drops over the rim hi honour of the household god, offered the first to Merlin. 'The guest cup, my lord. Health and long life be yours.'

She waited until he drained his cup before offering the next to me. I raised the cup to my mouth, but as the ruby liquid touched my lips I was overwhelmed by the urge to sneeze. I sneezed once, violently, and then again.

When I regained my composure, I once more lifted the cup to my mouth – only to sneeze yet again. Nimue glanced at me furtively. Was it concern? Or was it fear I saw in her eyes?

Seeking to reassure her, I apologized, saying, 'Wine sometimes has an unfortunate effect on me. Think no ill of it, but I will decline.' So saying, I replaced my cup on the board.

The evening passed pleasantly. We dined on the roast fowl and porridge, and talked of the affairs of the realm. Nimue was most interested in the news we brought, and asked many questions – questions which revealed a lively intellect and a wide knowledge of the world beyond her door. Certainly, we were not the first travellers to have sheltered beneath her father's roof.

After we had eaten and talked, it came into my mind to return to the horses. I was still a little anxious for them, and considered that it would do no harm to see them settled for the night. I stood up to take my leave, and Nimue came to me. Taking my hands, she said, 'Do not go, my lord. It is dark and you might fall into the pool.' 'I can swim,' I replied with a laugh, and stepped outside. It was a clear night, the moon bright overhead. I could see my way with ease, and began walking along the path. The pool shimmered in the moonlight, glowing like an earth-bound star. The horses stood flank to flank, heads down. They whickered softly as I approached. I stroked their necks gently and spoke to them. Then I examined the tether ropes, satisfied myself that they were secure, and started back.

I suppose I must have lost direction in the moonlight, for, after walking a fair way, I did not reach the house.

It is possible to become lost in unfamiliar places, especially in the dark. Yet I had no difficulty finding my way back to the pool. Then, as I sought to retrace my steps to the house, I heard singing – the same lilting voice I had heard before encountering Nimue – though I could see no one.

I continued on and inexplicably returned to the pool a short time later. I struck off once more along the path – certain that it was the correct path and not some other, for I was more careful to mind my way. Nevertheless, I soon found myself lost amidst a growth of elder bushes. And again I heard the eerie singing. I called out, but there was no answer. I waited and called again. The singing stopped.

Turning my steps once more to the pool, I marked that it took longer to regain it this time. The way had become confused and altered subtly.

At last I reached the pool, approaching now it from a different direction. This puzzled me, but instead of starting off once more, I sat down for a moment to think it out clearly.

The house was nearby – not more than a few hundred paces from the pool in any event. It did not seem possible that I could walk and miss the place: the moon was high and bright, the way easily marked.

Yet, thrice I had lost my way. Drawing a deep breath, I set off once more, careful to keep the pool at my back, ignoring the path and trusting my own quickly diminishing sense of direction.

I walked for a short while – much further than I remembered – and was about to turn back when I saw it. Directly ahead, shimmering in the moonlight, stood the house; the light from the hearthfire faintly glowing in the doorway. Smoke seeped slowly through the roof-thatch, silvery in the moonglow, rising like the vapours from a fetid fen.

I moved towards the light, and upon reaching the door I heard singing: soft, lilting, sweet; and yet I shivered to hear it. For, more than anything else, the sound possessed the haunting melancholy quality of a chill autumn wind through bare willow branches.

I paused on the threshold of the house and listened, but the last few notes trailed away into silence and the song was finished.

The horses are set – 'I began, then froze, staring.

Merlin lay on the floor near the hearth, his head in Nimue's lap. She held Merlin's knife in her hand. At my intrusion, her face turned towards me, and – I cannot be certain – but in the flickering firelight it seemed her features contorted in an expression of unutterable rage and contempt. And I felt as if a spear pierced my belly and twisted in my entrails.

Nimue smiled invitingly. Placing a long finger to her lips, she whispered, 'Your master is asleep.' She smoothed his hair and bent to kiss him.

My reaction was sharp and quick. Anger blazed through me like lightning. 'No! You cannot – ' I leapt forward, but she held up a hand and I halted.

'Shh! You will wake him!' Then, more softly, 'I was singing and he fell asleep… he was so tired.'

As quickly as it had erupted, the heat of my fury melted away and I stood looking on, feeling foolish and contrite. 'I am sorry,' I mumbled, 'I thought… '

Nimue smiled. 'Say no more. I understand.' She turned and, as if forgetting me, began stroking Merlin's head once more, then bent and kissed him chastely on the forehead, and replaced the knife in his belt. She murmured something over him and then carefully lowered his head and shoulders to the hearth.

She rose and came to me, smiling, and put her hands on my chest. 'Forgive me,' she whispered, putting her face close to mine. I caught the scent of apple blossoms on her breath. 'He looked so peaceful, I could not resist… '

Her lips parted, and her eyelids closed. She pressed her mouth against mine and I tasted the sweet warmth of her lips. I felt her fingers on my wrist, guiding my hand to her breast, and in that moment I wanted her as I have desired no other woman.

Nimue held her body next to mine, pressing her loins against my thigh. I felt her firm warm flesh beneath my hands and I ached for her.

The next thing I knew she was standing before the fire and her mantle was slipping to the floor.

Her body was exquisitely formed, flawless, its curved symmetry revealed by the shadows and light from the hearthfire. She turned, cupping her breasts with her hands, and walked slowly towards me, as if offering me the ripeness of her body.