The desert, the largest sand mass on Earth, was flanked to the north by the Saudi Arabian province of A1 Najd, to the east by the oil-rich region of Al Hasa based on the refinery complex near the city of Ad Dammam and the statelets of the United Arab Emirates, to the south by the hills of Oman and Yemen, to the west by the Saudi mountains of the Asir range. Whipped by the winds, the desert sands continually moved, lorming new peaks and patterns, and the great area that was a thousand kilometres wide and six hundred kilometres in depth was perpetually burned by the sun's ferocity. The itinerant Bedouin tribesmen, who alone could exist in the desert's privations, called it the Rub' al Khali, the Empty Quarter.

The dawn light, thrown low, caught the mahogany wings of a hunting eagle. It lit the dark upper coat of a stalking fox and highlighted the tracks of the jerboas that would be food for both the fox and the eagle. It glistened the still moist gobbet of phlegm spat out by a camel that had passed two days before. The light nestled on a point of black darkness between a cleft of rocks where higher ground rose above the western section of the sands.

Other than in the few minutes when the sun came up in the east, the entrance to the cave was hidden. A man emerged from it and blinked as the sun's brightness blinded him after a night in the dim interior. Behind him, in the depth of darkness, a petrol-driven generator started up and coughed before the engine engaged. He spat out the waste between his teeth and lit the first cigarette of the day.

Staring out over the expanse, he saw the single sentry squatting in a cleft below the cave's entrance, a rifle held loosely in his lap. He ground out the cigarette, then placed the butt in a small tin box; later it would go with other waste into a pit dug in the sand, then be covered up. He whistled to the sentry, who turned his head, smiled grimly, then shook it. Only the desert confronted them, not danger.