Hobart, however, did not have madness as a place of retreat, having been in its hold for years. The vision of fire that Shadwell had given him - and which had first claimed him for the Salesman's faction - obsessed him still, despite the fact that the coat had been discarded. Knowing that in Shadwell's company his obsession would not be mocked, Hobart elected to remain there. With Shadwell, his dreams had come closest to being realized; and, though their shared ambitions had been defeated, the man still spoke a language Hobart's dementia understood. When the Salesman talked of the Scourge, Hobart knew it could only be the Dragon of his dreams by another name. Once, he half-remembered, he'd sought that monster in a forest, but he'd found only confusion there. It had been a sham, that Dragon; not the true beast he still longed to meet. He knew where that legend waited now: not in a forest but a desert, where its breath had reduced all living matter to ash and sand.

They went together, therefore, to a village on the Southern fringe of the Quarter; a place so inconsequential it couldn't even lay claim to a name.

Here they were obliged to leave their jeep, and, with their driver as interpreter, pick up guides and camels. It was not simply the practical problems of crossing the Quarter by vehicle that made Shadwell forsake wheel for hooves. It was a desire - encouraged by Emerson - to be as much a part of the desert as was possible. To go into that void not as conquerors but as penitents.

Locating their two guides for the expedition was the business of an hour, no more, there being so few either willing or able-bodied enough to make the journey. Both men were of AM Murra tribe, who alone of all the tribes claimed spiritual kinship with the Quarter. The first, a fellow called Mitrak ibn Talaq, Shadwell chose because he boasted that he'd guided white men into the Rub al Khali (and back out again) on four previous occasions. But he would not go without the company of a younger man by the name of Jabir, whom he variously described as his cousin, half-cousin and brother-in-law. This other looked to be little more than fifteen, but had the scrawny strength and the worldly-wise glance of a man three times that age.

Hobart was left to haggle with them, though the terms of the arrangements took some time to sort out, as the Arabic he'd learned for this expedition was primitive, and the Arabs' English was bad. They seemed to know their profession however. The purchase of camels was the business of half a day; the purchasing of supplies another morning.

It was therefore the labour of a mere forty-eight hours to prepare for the crossing.

On the day of their departure, however, Shadwell - whose fastidiousness had not kept him from satisfying his belly -fell foul of an intestinal plague that turned his innards to water. With his gut in revolt he couldn't keep a morsel of food in his system long enough to profit by it, and he quickly became weak. Wracked by fever, and with access only to the most rudimentary medication, all he could do was take refuge in the hovel they'd hired, find the corner where the sun couldn't reach him, and there sweat the sickness out.

Two days passed, without his improving. He was not used to illness, but on those few occasions he had fallen sick he'd always hidden himself away, and suffered in private. Here, privacy was nearly impossible to find. All day he could hear scrabblings outside the door and window, as people fought for a chance to peer through the cracks at the infidel, moaning on his filthy sheet. And when the locals grew tired of the spectacle there were still the flies, watching over him, thirsty for the tainted waters at his lips and eyes. He'd long since learned the hopelessness of shooing them away. He simply lay in his sweat and let them drink, his fevered mind drifting off to cooler places.

On the third day Hobart suggested they postpone the journey, pay off Ibn Talaq and Jabir, and return to civilization. There Shadwell could regain his strength for another try. Shadwell protested at this, but the same thought had crept into his own head more than once. When the infection finally left his body, he'd be in no fit state to dare the Quarter.

That night, however, things changed. For one, there was a wind. It came not in gusts but as a steady assault, the sand it carried creeping in beneath the door and through the cracks in the window.

Shadwell had slept a little during the preceding day, and had benefited from his rest, but the wind prevented him from settling now. The disturbance got into his gut too, obliging him to spend half the night squatting over the bucket he'd been provided with, while his bowels gave vent.

That was where he was - squatting in misery in a cloud of flatulence - when he first heard the voice. It came out of the desert, rising and falling like the wail of some infernal widow. He'd never heard its like.

He stood up, soiling his legs in doing so, his body wracked with shudders.

It was the Scourge he was hearing, he had no doubt. The sound was muted, but indisputable. A voice of grief, and power; and summoning. It offered them a signpost. They would not have to go blindly into the wilderness, hoping luck would bring them to their destination. They'd follow the route the wind had come. Sooner or later wouldn't it lead them to the creature whose voice it carried?

He hoisted up his trousers and opened the door. The wind was running wild through the tiny town, depositing sand wherever it went, whining at the houses like a rabid dog. He listened again for the voice of the Scourge, praying that it was not some hallucination brought on by his hunger. It was not. It came again, the same anguished howl.

One of the villagers hurried past the spot where Shadwell stood. The Salesman stepped out of the doorway and took the man's arm.

'You hear?' he said.

The man turned his scarred face towards Shadwell. One of his eyes was missing.

'Hear?' said Shadwell, pointing to his head as the sound came again.

The man shook off Shadwell's grip.

'Alhiyal,' the man replied, practically spitting the words out.

'Huh?'

'Al hiyal. . .' he said again, backing away from Shadwell as from a dangerous idiot, his hand at the knife in his belt.

Shadwell had no argument with the man; he raised his hands, smiling, and left him to his troubles.

A curious exhilaration had seized hold of him, making his starved brain sing. They'd go tomorrow into the Quarter, and damn his intestines to Hell. As long as he could stay upright on a saddle he could make the journey.

He stood in the middle of the squalid street, his heart pounding like a jack-hammer, his legs trembling.

'I hear you,' he said; and the wind took the words from his lips as if by some perverse genius known only to desert winds it could return the way it had come, and deliver Shadwell's words back to the power that awaited him in the void.

II.

OBLIVION.

1.

Nothing, neither in the books he'd read nor the testimonies he'd listened to, nor even in the tormented voice he'd heard on the wind the previous night, had prepared Shadwell for the utter desolation of the Rub al Khali. The books had described its wastes as best words could, but they couldn't evoke the terrible nullity of the place. Even Emerson, whose mixture of understatement and passion had been persuasive in the extreme, hadn't come near to touching upon the blank truth.

The journey was hour upon relentless hour upon relentless hour of heat and bare horizons, the same imbecile sky overhead, the same dead ground beneath the camels' feet.

Shadwell had no energy to waste on conversation; and Hobart had always been a silent man. As for Ibn Talaq and the boy, they rode ahead of the infidels, occasionally whispering, but mostly keeping their counsel. With nothing to divert the attention, the mind turned to the body for its subject, and rapidly became obsessed with sensation. The rhythm of the thighs as they chafed against the saddle, or the taste of the blood from the lips and gums; these were thought's only fodder.

Even speculation about what might lie at this journey's end was lost in the dull blur of discomfort.

Seventy-two hours passed without incident: only the same curdling heat, the same rhythm of hoof on sand, hoof on sand, as they followed the bearing of the wind on which the Scourge's voice had come. Neither of the Arabs made any enquiry as to the infidels' purpose, nor was any explanation offered. They simply marched, the void pressing upon them from all sides.

It was worse by far when they stopped, either to rest the camels, or to offer their sand-clogged throats a dribble of water. Then the sheer immensity of the silence came home to them.

Existence here was an irrational act, in defiance of all physical imperatives. What kind of creature had chosen to make its home in such an absence, Shadwell wondered at such moments: and what force of will must it possess, to withstand the void? Unless - and this thought came more and more - it was of the void: a part of the emptiness and silence. That possibility made his belly churn: that the power he sought belonged here - chose dunes for its bed and rock for its pillow. He finally began to understand why Immacolata's visions of the Scourge had brought sweat to her brow. In those nightmares she had tasted a terrible purity, one that had made her own pale by its light.

But he was not afraid; except of failing. Until he stepped into the presence of that creature - until he learned the source of its cleanliness, he could not be cleansed himself. That he longed for above all things.

And, as the night fell on their fourth day in the Quarter, that desire came still closer to being realized.

Jabir had just set the fire when the voice came again. There was little wind tonight, but it rose with the same solemn authority as before, tainting the air with its tragedy.

Ibn Talaq, who'd been cleaning his rifle, was the first to his feet, his eyes wide and wild, either an oath or a prayer on his lips. Hobart was on his feet seconds later, while Jabir went to soothe the camels, who had panicked at the sound and were tearing at their tethers. Only Shadwell stayed beside the fire, gazing into the flames as the howl - sustained as if on one monumental breath - filled the night.

It seemed to go on for minutes before it finally died away.

When it did it left the animals muttering, and the men silent. Ibn Talaq was first back to the fire, and the business of rifle-cleaning; the boy followed. Finally, Hobart too.

'We're not alone,' said Shadwell after a time, his gaze still on the flames.

'What was it?' said Jabir.

'Al hiyal,' Ibn Talaq said.

The boy pulled a face.

'What is al hiyal? Shadwell said.

They mean the noise the sand makes,' Hobart said.