But Billson had probably measured straight lines on a map and set out on that basis. But that was water under the bridge or, more accurately, vapour through the carburettor. What we had now was an entirely different set of circumstances in which Billson's idiocy didn't figure because, if we found his body it would be because he had been murdered by a man, and the man was possibly called Kissack.

It was then that I made the discovery. Mokhtar or Byrne would probably have done it, but they didn't – I did, and it brought back some of my self-respect as a working member of this crazy expedition and made me feel something less of a hanger-on while others did the work.

I was looking down idly at the rock on which I sat when I noticed a small brown stain over which an ant was scurrying. For a moment I wondered how even an ant could live in Koudia, and then I noticed another and then another. There was quite a trail of them going backwards and forwards between a crack in the rock and the stain.

I stood up, looked at the Land-Rover, took a line on it, and then explored further away. Sure enough ten yards further on there was another stained rock, and a little way along there was another. I turned. 'Hey!'

'What is it?'

'I think I've found something.' Byrne and Mokhtar came up and I said, 'Is that dried blood?'

Mokhtar moistened the tip of his little finger and rubbed it on the stain, then he sniffed his fingertip delicately, looked at Byrne, and said one word. 'Yeah,' said Byrne. 'It's blood.'

'There's a line of it coming from the Land-Rover.' I turned and pointed towards a narrow ravine. 'I think he went up there.'

'Okay – Mokhtar goes first; he's better at this than we are. He can see a sign you wouldn't know was there.'

Billson, if it was Billson's blood, had gone up the ravine but fairly soon it became obvious that he hadn't travelled in a straight line. Not because of the difficulty of the terrain because he had dodged about quite a bit when he had no obvious need to, and on occasion he had reversed his course. And the blood splashes got bigger.

'Hell!' I said. 'What was he doing? Playing hide-and-seek?'

'Maybe he was at that,' said Byrne grimly. 'Maybe he was being chased.'

We found him at last, tumbled into a narrow crack between two rocks where there was shade. Mokhtar gave a cry of triumph and pointed downwards and I saw him sprawled on sand which was bloodstained. His face wasn't visible so Byrne gently turned him over. 'This Billson?'

'I wouldn't know,' I said. 'I've never seen him.'

Byrne grunted and felt about the body. The face of the map was puffy and swollen and his skin was blackened. Incongruously, he was wearing a normal business suit – normal for England, that is. At least I had had the sense to visit a tailor to buy what was recommended as suitable attire for the desert, even if the tailor had been wrong to the point of being out of his mind. The probability rose that this was indeed Billson.

Byrne said, 'Whoever the guy is, he has a hole in him. He's been shot.' He held out his fingers, red with liquid blood.

'He's alive!' I said.

'Not for long if we don't do something.' Byrne spoke to Mokhtar, who went away fast. He then turned the man over so that he lay more easily and put his hand inside his jacket to withdraw a passport and a wallet from the inside breast pocket. He flipped open the passport one-handedly. 'This is your boy; this is Paul Billson.' He gave me the passport and wallet.

I opened the wallet. It contained a sheaf of Algerian currency, a smaller wad of British fivers, and a few miscellaneous papers. I didn't bother to examine them then, but put the passport and the wallet into my pocket.

'We're in trouble,' said Byrne. He indicated Billson. 'Or he is. If he stays another night he'll die for sure. If we try to take him out he'll probably die. You know how rough it'll be getting back to Assekrem; I don't know if he can take it in his condition.'

'It's a question of the lesser of two evils.'

'Yeah. So we try to take him out and hope he survives.' He looked down at Billson. 'Poor, obstinate bastard,' he said softly. 'I wonder how well Hesther knew his old man? She said in her note to you that she'd wired me. I didn't tell you it was a ten-page cable, and she was pretty firm and detailed in her instructions.'

'Has the flow of blood stopped?' I asked.

'Yeah; I have the tail of his shirt wadded into the hole. We can't do much until Mokhtar gets back. He won't be long.'

'You must have known about Paul Billson before I arrived.'

'Sure I did, but he'd taken off by then.'

I said, 'If you hadn't waited for me you could have got here earlier.'

'Not much. I got Hesther's cable the morning you came. I don't know when she sent it, but the communications in this country aren't noted for reliability.'

'But you did lead me a little way up the garden path.' It seemed odd to be making conversation over the body of a man who was probably dying.

Byrne said, 'I wanted time to size you up. I don' t like to travel with people I can't trust. Hereabouts it can be fatal.'

'So I passed the examination,' I said flatly.

He grinned. 'Just by a hair.'

A shadow fell athwart us. Mokhtar had come back. He had brought cloth for bandages, water, and a couple of sand ladders. The sand ladders, as Byrne had earlier explained, were to put under the wheels of the Toyota if we got stuck in sand. They were about six feet long and of stout tubular steel. 'Only stinkpots need them,' Byrne had said. 'Camels don't.'

Byrne tore off a strip of cloth, soaked it in water and put it in Billson's mouth; being careful not to choke him. Then he proceeded to dress the wound while Mokhtar and I lashed the sand ladders together to make an improvised stretcher.

It took us over an hour to get Billson the comparatively short distance back to the Toyota.

CHAPTER FIFTEEN

We had travelled two hours' worth into Koudia but it took us four hours to get out from the time Byrne started the engine until we drove beneath the peak of Assekrem. He picked his way as delicately as he could through that rocky desolation but, even so, Billson took a beating. Fortunately, he knew nothing of it; he was unconscious. I tended him as best I could, cushioning his body with my own, bathing his face, and trying to get some water into him. He did not move voluntarily nor did he make a sound.

I had expected Byrne to stop at Assekrem where perhaps we could have got help from the Haratin at the Hermitage, but he drove past the beginning of the path up the cliff and we camped about three miles further on. Mokhtar took a roll of cloth from the back of the Toyota and very soon had a windbreak erected behind which we laid Billson. It was now dark so Byrne redressed the wound in the acid light of a glaring pressure lantern.

He sat back on his heels and watched Mokhtar administer a salve to Billson's blackened face. 'If we can get some water into him he might survive,' he said. 'That's only a shoulder wound and the bullet went right through without hitting bone. Weakening but not killing. He's suffered more from exposure than the wound.'

I said, 'Why didn't you stop at Assekrem? They might have had something to help him.'

'Not a chance.' He nodded towards the Toyota. 'I have more stuff in my first aid kit than there is in the whole of the Ahaggar, if you except the hospital at Tarn. Besides…' His voice tailed away, which was odd in Byrne because he was usually pretty damned decisive.

'What's the matter?'

'Do you know anything about Algerian law?'

'Not a thing.'

'Well, Billson broke one of them. He came out here without a per mis.'

'So did you.'

'But I didn't apply for one – he did. You can be sure that when he disappeared from Tarn they knew where he'd gone.