I know that dad — who had indeed assumed that Rory had been on his way here — drove the Glasgow road a few times, immediately after Andy and then Janice raised the alarm, looking for some sign of an accident, a skid mark, a damaged fence or wall, always wondering if maybe his brother was lying unconscious or paralysed in a field or a ditch somewhere, invisible from the road… But all he ever found were road cones, assorted litter and the occasional dead sheep or deer.

Whatever; neither dad nor the police ever found any trace of Rory or the bike. No unidentified bodies turned up that could have been his, and no hospitals received any unknown coma victims fitting his description.

I don't think any of us ever mentioned suicide, but I at least considered the possibility that he had killed himself. Rory had been depressed, after all; his one success had been a travel book written a decade earlier, and everything else he'd tried since had failed to live up to that; he had recently failed to become a TV presenter — a job he'd thought beneath him but which he needed for the money (and so had been all the more galled when he hadn't been chosen) — and maybe, too, he'd finally admitted to himself he was never going to write his magnum opus…

Hell, his life just wasn't going anywhere special; people kill themselves for poorer reasons.

I reckoned the chances of him being under the waves somewhere improved significantly if he had committed suicide; he could have picked his spot to drive straight at a wall or a crash barrier, maybe on top of a cliff. Could be anywhere. I could think of a few places, further north in the Highlands, which would be perfect. If he'd tied himself to the bike somehow…

But why go to the effort of doing that in the first place? It wasn't as though there was some big insurance sum involved, or any funny business with wills or family money. Rory had inherited some capital when grandad died, held in trust until he was eighteen; he'd used that up travelling round India the first time, then lived off the success of Traps and — later — the declining advances and journalistic commissions he'd received after that. When he'd disappeared he'd had a small overdraft.

Maybe he'd been murdered. I'd thought of that years ago, even on the evening we'd heard he was missing. I had been playing down on the shore of Loch Gair with Helen and Diana Urvill, and when we came back for our tea there was a police car in the courtyard of the house.

A police car! I recall thinking, getting all excited.

Of course, in my fantasy I was the one who discovered Rory's evil murderer and brought him to justice, or fought with him and watched him fall off a cliff or into a combine harvester or under a steam-roller or whatever.

Only I couldn't see that anybody had had much of a motive. It had crossed my mind that it might have something to do with Crow Road; somebody wanted to steal the idea and keep Rory out of the way, but it wasn't even as though there was much to steal. Notes and poems; wow.

I stood up on the silent concrete block and dusted my hands off. The disappearing clouds were the colour of dried blood in a sky gone close to purple. More stars were coming out. A contrail blazed pink overhead, as a plane headed for America. I looked at my watch; I had to go. I'd told mum I'd be back for supper in an hour or so. We were expecting Lewis and Verity that evening; they were flying up from London, where Lewis had been working, and they would hire a car at Glasgow. They might be back when I returned.

"Shouldn't have mentioned you," Uncle Hamish said, as I walked to the door of the dim bedroom. I turned back. He was still trembling. It hurt me to look at him, the way it hurts to hear nails scraped down a blackboard. "Shouldn't have said anything about you, Prentice," he said, the words whistling out between his clenched teeth. I could hear Aunt Tone's footsteps coming up the stairs in the hall outside. "Shouldn't have said, Prentice; shouldn't have said."

"Said what, uncle?" I said, hand on the door knob.

"That you were closer to me; that I'd won you, saved you from his heathen faith!" Uncle Hamish's eyes stared at me from a shaking, ash-grey face.

I nodded and smiled at him. "Oh well," I said. The door opened and I got out of the way of Aunt Tone, bearing pills and a glass of water. "See you tomorrow, Prentice," she whispered to me. She patted my arm. "Thank you."

"It's all right. See you tomorrow, Aunt Tone."

Outside, on the landing, I looked down the stairs to where my mother was standing by the front door, putting on her jacket. I leant back against the closed bedroom door for just a second, and — looking at nothing in particular — said very quietly to myself, "See?"

I went to the land-side edge of the concrete cube, and faced back at the remains of the sunset, trying to work out how I was going to feel seeing Lewis and Verity again, after the way I'd behaved at New Year. But search as I tried, I could find no trace of dread or jealousy; I was even looking forward to seeing them again. Something of the coldness that had settled over me in the last few days seemed to have spread to the way I felt about Verity. It felt like all my jealous passion had dissipated like the clouds overhead.

I thought about jumping down onto the beach, but that might have been asking for another family tragedy, so I climbed down, walked to the end of the shallow scoop of bay and set off through the grass by the side of the burn, heading back to Gallanach through the calm summer gloaming.

…He told us about the plants on the islands, too; how the open, glorious machair, between the dunes and the farmed land, was so dizzily sumptuous with flowers because it was the place where the acidic peat and the alkali sands produced a neutral ground where more plants could flourish in the sunlight. And just the names of those plants were a delight, almost a litany; marsh samphire, procumbent pearlwort, sand-spurrey, autumnal hawkbit, cathartic flax, kidney vetch, germander speedwell, hastate orache, sea spleenwort; eyebright.

We learned about the people who had made Scotland their home: the hunter-gatherers of eight or nine thousand years ago, nomads wandering the single great wood and stalking deer, or camping by the edge of the sea and leaving only piles of shells for us to find; the first farmers, just beginning to clear the land of the blanket of thick forest a few millennia later; the neolithic people who had built the tomb of Maes Howe before the pyramids were constructed, and the stone circle at Callanish before Stonehenge, in the thousand-year summer of the third millenium; then came the Bronze Age and Iron Age people, the Vikings and Picts, Romans and Celts and Scots and Angles and Saxons who had all found their way to this oceanically marginal little corner of northern Europe, and left on the place their own marks; the treeless slopes themselves, the roads and walls, cairns and forts, tombs, standing stones, souterrains, crannogs and farms and houses and churches; and the oil refineries, nuclear power stations and missile ranges, too.

He made up stories, about the secret mountain, and the sand-drowned forest, the flood that turned to wood, the zombie peat, and the stone-beings that drilled for air. Sometimes the location for, or the subject of, a story would have some basis in fact; the secret mountain was a real hill on which grew a flower that grew nowhere else in the world. There had indeed been great storms that had moved whole ranges of sand dunes inland, drowning forests, and villages… And peat was un-dead, the surrounding rocks" acidity, the chill Atlantic airs and ever-likely rain conspiring to prevent the corpses of the dead plants from decomposing.

Other stories were pure fantasy, the result of a kind of child-like quality in him, I think. If you looked at certain stands of trees from a distance, especially in a glen, and when in full leaf, they did look like great bulging torrents of green water, bursting from the depths of the earth and somehow frozen. There was a sort of visual naivety at work there that verged on the hallucinogenic, but it did, I'd argue, make a warped sort of visual sense. Magmites — the people who lived in the mantle of the earth, beneath the crust, and who were drilling up for air the way we were drilling down for oil — must just have appealed to that part of him that loved turning things around. Opposites and images fascinated him, excited him; magicked inspired absurdity from him.