Fachi was a small, miserable oasis a little over a hundred miles from the Tree of Tenere. The people were Negroid and the women wore rings in their noses. 'These people are Fulani,' said Byrne with an edge of contempt in his voice. The Tuareg don't like 'em, and they don't like the Tuareg. We're not staying here – they'd steal us blind.'

We stopped only long enough to fill the water cans and to buy a goat kid which Byrne efficiently lulled and butchered, then we went on for ten miles and camped just as the sun was setting. We cooked a meal, then ate and slept, and were on our way again at dawn next day.

We drove mile after rolling mile among the dunes and sometimes over them when there was no other recourse. Once I said to Byrne, 'How the devil do you know which way to go?'

'There's an art in that, too,' he said. 'You've got to know what the prevailing wind was during the last few months. That sets the angle of the dunes and you can tell your direction by that. It don't change much from year to year but enough to throw you off and get you lost. And you keep an eye on the sun.'

It was nearly midday when we rose over the crest of a dune and Byrne said, 'There's the azelai'

'What?'

'The salt caravan Mokhtar is taking to Bilma. He's two days out of Fachi.'

That gave me a clue as to the difference between the speed of a camel and that of a Toyota. 'How long from Agadez to Bilma?'

'Four weeks. Two or three weeks in Bilma to rest up, then back again with the salt. Best part of three months for the round trip.'

The caravan consisted of about three hundred camels and perhaps twenty camel drivers. 'Fifty of these are mine,' said Byrne, and hailed Mokhtar. He came towards the truck with the slow, lazy saunter of the Tuareg, looked at me in surprise, and then laughed and said something to Byrne who chuckled and said, 'Mokhtar thinks I've got a convert. He wants to know if I'm setting up in competition with the Prophet.'

He examined his animals and expressed satisfaction at their condition, and then we went on, and the caravan, plodding its slow three-miles-an-hour pace, was soon left behind.

It was at about three that afternoon when the offside front tyre burst and the steering-wheel slewed violently in Byrne's hands. 'Goddamn!' he said, and brought us to a halt.

There was a whipcrack at my ear and the windscreen shattered. I had. been shot at in Korea and I knew a bullet when I heard one, even without the evidence of the broken windscreen. 'Everyone out,' I yelled. 'We're under fire.'

I jerked at the door handle and jumped out. The bullet had come from my side, so I ran around the truck to get into cover. As I did so a fountain of sand spurted a yard ahead of me. Paul was still in the truck, not being quick enough off the mark, and I found Byrne hauling him out. I discovered that I was holding the Walther pistol in my hand although I couldn't remember drawing it The shooting was still going on, sharp cracks in the dead, dry air. I judged it to be a rifle. But no bullets were coming anywhere near us. Byrne nudged me. 'Look!' He pointed upwards to the dune behind us.

Konti, the Teda, was running up the dune and was already three-quarters of the way to the top, which was about sixty feet. His gandoura fluttered in the breeze of his passage, and bullets sent the sand flying about his feet. At the top, silhouetted against the sky, he seemed to stumble, then he fell rather than jumped over the other side of the dune and was gone from sight. The shooting stopped.

'Think he was hit?'

'Don't know,' said Byrne, and opened the rear door of the Toyota. He put his arm inside and withdrew the Lee-Enfield rifle. 'I think Kissack got ahead of us.' He took a full magazine from the pouch at his neck and loaded the rifle.

There was another shot and a thump, then the metallic howl of a ricochet off metal. The truck quivered on its springs. 'The bastards have us pinned down,' said Byrne. 'If we try to make a run for it now we'll be dead meat.' He looked up at the dune behind us. 'That guy only got away because he did the unexpected. I guess he's been shot at before.'

'If he did get away.'

Another bullet slammed into the side of the truck.

'Yeah.'

I looked around for Billson and found him scrunched up behind the rear wheel, making himself as small as possible. Byrne followed my glance. 'He won't be much help,' he said flatly. 'We can count him out.'

'So what do we do?'

'Shoot back.'

There was a (hunk and a soft explosive blast of air as another tyre went. Byrne said. 'He does that once more and we're stuck. I only have two spares. See if you can locate the son of a bitch.'

Carefully I raised my head, looking through the windows of the Toyota. I stared at the dune I saw which was about a hundred feet high, and ran my eye along the line of the crest. There was another shot which hit the truck and then I saw a slight movement.

I ducked down. 'He's on top of the dune and about twenty d egrees to the left'

'How far?'

'Hard to say. Two fifty to three hundred yards. It'll be an uphill shot.'

'Uh-huh!' Byrne adjusted the sight on the rifle. 'Now let the dog see the rabbit. And, for Christ's sake, keep that handgun ready and watch our flanks.'

I stood back at a crouch as Byrne pushed the barrel of the rifle through the open window in the door of the truck. I glanced from side to side but nothing moved. 'I see him,' said Byrne softly. They fired together and Byrne ducked. The truck shivered on its springs. 'I think I put some sand in his eyes,' he said.

There was silence broken only by metallic creakings from the cooling engine and a soft liquid gurgling noise. I was beginning to think Byrne was right when there came another shot and a bullet went right through both open windows of the truck, breaking the sound barrier about six inches above my head with a vicious crack.

Byrne said, 'I'll bet he moved. If I can do that again be ready to make a break for it. Then try to out-flank them. If we don't do something we'll be shot to bits just standing here.'

'All right'

He raised his head and looked up at the dune. 'Yeah, he moved. Now where in hell is he?' Another bullet came our way with disastrous effect. It slammed into the tyre on the wheel behind which Billson crouched and there was a whoosh as the air escaped.

That's buggered it!' said Byrne. Paul was whimpering and trying to burrow his way into the soft sand. 'We won't get far on three wheels, but I've got the bastard spotted.'

He brought up the rifle again and prepared to fire. I said, 'Hold it, Luke!' and put all the urgency I could into my voice.

He lowered his head. 'What is it?'

I knew what that gurgling noise had meant. 'He's either got the petrol tank or one of the fuel cans. Can't you smell it?' Byrne sniffed the stink of petrol. I said, 'You shoot that thing and we could go up in flames in a big way. It only needs a spark.'

'Jesus!' He withdrew the rifle and stared at me, and the same thing was in both our minds. It would need only a spark from a ricochet off metal to fire the vapourizing petrol.

I said, 'I made that mistake in Korea, and I've got burned skin to prove it.'

'I wondered about that puckering on your chest. We'd better run for it then. Different directions. I think there's only one guy shooting; he won't get us both.'

'What about Paul?'

'He can do what the hell he likes.' A bullet smashed into a headlight and glass flew. 'All right,' I said. 'Immediately after the next shot' Byrne nodded.

There was no next shot – not from the rifle, but faintly in the distance someone screamed, an ululating noise of pure agony which went on and on. I jerked, torn from the tension of waiting to run into a greater tension. I stared at Byrne. 'What's that?'

The scream still went on, now broken into sobbing screeches as someone fought for breath. 'Someone's hurting, that's for sure,' he said. There were distant shots, not from the rifle but from pistols in my judgement. Then the screaming stopped and again there was silence.