It was a violin, playing a sweet, plaintive melody, light and slow and shot through with a profound and permanent sadness. I had never, to my knowledge, heard the tune before, although it had the bone-deep familiarity possessed by all things that are very old. I did, however, know the hands that wielded the bow.

"Holmes?" I said into the dark.

He finished the verse, drawing out the long final note, before he allowed the instrument to fall silent.

"Hello, Russell. You took your time."

"Holmes, I hope there is a good reason for this."

He did not answer, but I heard the familiar sounds of violin and bow being put into a case. The latches snapped, followed by the vigorous rustle of a waterproof being donned. I turned on the torch in time to see Holmes stepping out of the small shelter of a roofed gate set into a stone wall. He paused, looking thoughtfully at the telltale inundation of mud up my right side to the elbow, the result of a misstep into a pothole.

"Why did you not use the torch, coming up the road?" he asked.

"I, er…" I was embarrassed. "I thought there was someone following me. I didn't want to give him the advantage of a torch-light."

"Following you?" he said sharply, half-turning to squint down the road.

"Watching me. That back-of-the-neck feeling."

I saw his face clearly by the light of the torch. "Ah yes. Watching you. That'll be the moor."

"The Moor?" I said in astonishment. I knew where I was, of course, but for an instant the book I had been reading on the train was closer to mind than my sense of geography, and I was confronted by the brief mental image of a dark-skinned scimitar-bearing Saracen lurking along a Devonshire country lane.

"Dartmoor. It's just there." He nodded over his shoulder. "It rises up in a great wall, four or five miles away, and although you can't see it from here, it casts a definite presence over the surrounding countryside. You'll meet it tomorrow. Come," he said, turning up the road. "Let us take to the warm and dry."