Then I see another man appear at the top of the dune. He is tall and muscular and dressed in some savage's light armour; his golden arms and legs are bare. He carries a huge sword, and a decorated helmet, which he holds in the crook of one arm. He looks transparent and unsubstantial, for all his bulk. I can see through his body: perhaps he is a ghost. The sword glitters in the sunlight, but dully. He sways as he stands there, not seeing me. He puts one hand shakily to his brown, then seems to talk to the helmet he holds. He half-walks, half-staggers down the slip face towards me, his booted feet and thickly muscled legs plunging through the baking sand. Still he does not appear to notice me. His hair is bleached by the sun; peeling skin covers his face and arms and legs. The sword drags in the sand behind him. He stops at my feet, staring into the distance, swaying. Has he come to kill me with that great sword? At least it might be quick.

He stands, still swaying, eyes fixed on the hazy distance. I would swear he is standing too close to me, too close to my feet; as though his own feet were somehow inside mine. I lie, waiting. He stands above, struggling to keep on his feet, one arm going out suddenly as he tries to balance himself. The helmet in the crook of his arm falls to the sand. The helmet's decoration, a wolf's head, cries out.

The warrior's eyes turn up into his head, going white. He crumples, falling towards me. I close my eyes, ready to be crushed.

I feel nothing. I hear nothing, either; he does not fall onto the sand beside me, and when I open my eyes there is no trace of him or the helmet he dropped. I stare into the sky again, at the entwined double-spiral of circling birds that are death.

I used the last of my strength to peel open my coat and jacket and bare my chest to the invisible, turning bolt in the sky. I lay, spreadeagled, for some time; two of the birds landed near me. I did not stir.

One of them swiped at my hand with its hooked beak, then jumped back. I lay still, waiting.

When they came for my eyes I took them by their necks. Their blood was thick and salty, but like the taste of life to me.

I see the bridge. At first I am certain it is a hallucination. Then I believe it might be a mirage, something which looks like the bridge reflected in the air and - to my parched, obsessed eyes - taking on its form. I walk closer, through the heat and the slopes of clinging, flowing grains. I have the handkerchief over my head, shading me. The bridge shimmers in the distance, a long rough line of summits.

I come slowly closer to it throughout the day, resting only for a short while when the sun is at its height. Sometimes I climb to the tops of the long dunes, to reassure myself it is there. I am within a couple of miles before my confused eyes admit the truth to me; the bridge is in ruins.

The main sections are largely intact, though damaged, but the linking sections, those spans, those little bridges within bridges, they have collapsed or been destroyed, and large parts of the section extremities have disappeared along with them. The bridge looks less like a succession of laterally stretched hexagons and more like a line of isolated octagons. Its feet still stand, its bones still rise, but its linking arms, its connections - they have gone.

I see no movement, no sudden glints of light. The wind sighs sand over the edges of dunes, but no sound comes from the tall ochre skeleton of the bridge. It stands, blanched and gaunt and jagged in the sand, slow golden waves lapping at its granite plinths and lower buildings.

I enter its shadow at last, gratefully. The burning wind moans between the towering girders. I find a staircase, start to climb. It is hot and I am thirsty again.

I recognise this. I know where I am.

Everywhere is deserted. I see no skeletons but I find no survivors. The train deck holds a few old carriages and locomotives, rusted to the rails they stand upon; finally part of the bridge. Sand has blown up even here, shading yellow-gold into the edges of the rails and points.

My old haunt, indeed. I find Dissy Pitton's. It is a fallen place; the ropes which used to attach tables and chairs to ceiling have mostly been cut; the couches and seats and tables lie sprawled over the dusty floor like bodies from long ago. A few hang by one edge or corner; cripples among the dead. I walk to the Sea View Lounge.

I sat here once with Brooke. Right here. We looked out and he complained about the barrage balloons; then the planes flew past. The desert is bright under the high sun.

Dr Joyce's office; not his. I do not recognise any of this furniture, but then he was always moving. The blinds, blowing in and out gently behind the broken windows, look the same.

A long walk takes me to the Arrols' abandoned summer apartment. It is half-submerged in the sand. The door is open. Only the tops of the still sheet-covered pieces of furniture are visible. The fire is buried beneath the waves of sand; so is the bed.

I climb slowly back to the train deck and stand, looking out over the shimmering sands which surround the bridge. An empty bottle lies at my feet. I take it by the neck and throw it from the train deck. It curves, end over end, glinting in the sunlight, towards the sand.

A wind comes up later, screaming through the bridge; scouring me, flailing me. I hug myself in a corner, watching the edge of the wind strip paint from the bridge like some endless rasping tongue. 'I give in,' I tell it.

The sand seems to fill my brain. My skull feels like the bottom of an hourglass.

'I give in. I don't know. Thing or place; you tell me.' I think this is my own voice. The wind blows harder. I cannot hear myself speak, but I know what I am trying to say. I am suddenly certain that death has a sound; a word which anybody may utter which will cause and be their death. I am trying to think of this word when something grates and swivels in the distance, and hands lift me away from this place.

Let's get one thing absolutely straight: it's all a dream. Either way, whatever. We both know that.

I have a choice, however.

I am in a long, hollow, echoing place, lying in bed. There are machines around me, drips into me. People come and look at me, occasionally. The ceiling sometimes looks like white plaster, sometimes like grey metal, sometimes like red brick, sometimes like riveted sheets of steel painted the colour of blood. Finally, I realise where I am; inside the bridge, within its hollow metal bones.

Fluid seeps into me through my nose and out again via a catheter. I feel more like a plant than an animal, a mammal, an ape, a human. Part of the machine. All the processes have slowed. I have to find a way back; blow the tanks, pull the cord; floor the throttle?

Some of these people look familiar.

Dr Joyce is here. He wears a white coat and he makes notes on a clipboard. I'm sure I saw Abberlaine Arrol, just fleetingly, a while ago ... but she was dressed in the uniform of a nurse.

This place is long and echoing. Sometimes I smell iron and rust, and paint and medicines. They took away the card I was given, and the scarf... I mean the handkerchief.

Ah, coming round, are we? Dr Joyce smiles at me. I look up at him, try to speak: Who am I? Where am I? What is happening to me?

We have a new treatment, the doctor says to me, as though to a particularly dim child. Would you like us to try it? Would you? It might make you better. Sign this.

Gimme gimme. In blood if you like. Give you my soul if I thought I had one but never mind. How about a tranche on a few billion neurons? Nicely run-in brain here doc; one careful owner (ahem); didn't even take it to church on Sundays... Bastards; it's a machine.