I reached the deep furrow in the snow inside a minute – I'd switched off my torch to conserve the battery but my stumble and heavy fall as I went over the edge was intimation enough – turned right and reached the plane in thirty seconds. I suppose I might possibly have lasted out the night inside the wrecked fuselage, but such was my singleness of purpose at the moment that the thought never occurred to me. I walked round the wing, picked up the first of the bamboos in the dim beam of my torch and started to follow them.

There were only five altogether. After that, nothing. Every one of the others had been removed. These five, I knew, pointed straight towards the cabin and all I had to do was to keep shifting the last of the five to the front, lining it up straight with the others in the light of my torch, and it would be bound to bring out to the cabin. Or so I thought, for perhaps ten seconds. But it was a task that really required two people to achieve anything like accuracy: what with that, the feebleness of my rapidly dying torch and the hopeless visibility, I couldn't be accurate within two or three degrees at the least. That seemed a trifle, but when I stopped and worked it out I discovered that, over the distance, even one degree out would have put me almost forty feet off course. On a night like that, I could pass by the cabin ten feet away and never see it. There were less laborious means of committing suicide.

I picked up the five sticks, returned to the plane and walked along the furrowed trench till I came to the depression where the plane had touched down. The 250-foot line of the antenna, I knew, was roughly four hundred yards away, just a little bit south of west – slightly to my left, that was, as I stood with my back to the plane. I didn't hesitate. I strode out into the darkness, counting my steps, concentrating on keeping the wind a little more than on my left cheek but not quite full face. After four hundred long paces I stopped and pulled out my torch.

It was quite dead – the dull red glow from the filament didn't even register on my glove six inches away, and the darkness was as absolute as it would ever become on the ice-cap. I was a blind man moving in a blind world, and all I had left to me was the sense of touch. For the first time fear came to me, and I all but gave way to an almost overpowering instinct to run. But there was no place to run to.

I pulled the drawstring from my hood and with numbed and clumsy hands lashed together two of the bamboos to give me a stick seven feet in length. A third bamboo I thrust into the snow, then lay down flat, the sole of my boot touching it while I described a complete circle, flailing out with my long stick into the darkness. Nothing. At the full stretch of my body and the stick I stuck the last two bamboos into the snow, one upwind, the other downwind from the central bamboo, and described horizontal flailing circles round both of these. Again, nothing.

I gathered up the bamboos, walked ten paces more, and repeated the performance. I had the same luck again – and again and again. Five minutes and seventy paces after I had stopped for the first time I knew I had completely missed the antenna line and was utterly lost. The wind must have backed or veered, and I had wandered far off my course: and then came the chilling realisation that if that were so I had no idea now where the plane lay and could never regain it. Even had I known the direction where it lay, I doubted whether I could have made my way back anyway, not because I was tired but because my only means of gauging direction was the wind in my face, and my face was so completely numbed that I could no longer feel anything. I could hear the wind, but I couldn't feel it.

Ten more paces, I told myself, ten more and then I must turn back. Turn back where, a mocking voice seemed to ask me, but I ignored it and stumbled on with leaden-footed steps, doggedly counting. And on the seventh step I walked straight into one of the big antenna poles, staggered with the shock, all but fell, recovered, grabbed the pole and hugged it as if I would never let go. I knew at that moment what it must be like to be condemned to death and then live again, it was the most wonderful feeling I had ever experienced. And then the relief and the exultation gradually faded and anger returned to take its place, a cold, vicious, all-consuming anger of which I would never have believed myself capable.

With my stick stretched up and running along the rimed antenna cable to guide me, I ran all the way back to the cabin. I was vaguely surprised to see shadows still moving in the lamp-lit screen that surrounded the tractor – it was almost impossible for me to realise that I had been gone no more than thirty minutes -but I passed by, opened the hatch and dropped down into the cabin.

Joss was still in the far corner, working on the big radio, and the four women were huddled close round the stove. The stewardess, I noticed, wore a parka – one she had borrowed from Joss – and was rubbing her hands above the flame.

"Cold, Miss Ross?" I inquired solicitously. At least, I had meant it to sound that way, but even to myself my voice sounded hoarse and strained.

"And why shouldn't she be, Dr Mason?" Marie LeGarde snapped. "Dr Mason', I noted. "She's just spent the last fifteen minutes or so with the men on the tractor."

"Doing what?"

"I was giving them coffee." For the first time the stewardess showed some spirit. "What's so wrong in that?"

"Nothing," I said shortly. Takes you a damned long time to pour a cup of coffee, I thought savagely. "Most kind, I'm sure." Massaging my frozen face, I walked away into the food tunnel, nodding to Joss. He joined me immediately.

"Somebody just tried to murder me out there," I said without preamble.

"Murder you!" Joss stared at me for a long moment, then his eyes narrowed. "I'll believe anything in this lot."

"Meaning?"

"I was looking for some of the radio spares a moment ago – a few of them seem to be missing, but that's not the point. The spares, as you know, are next to the explosives. Someone's been tampering with them."

The explosives!" I had a momentary vision of some maniac placing a stick of gelignite under the tractor. "What's missing?"

"Nothing, that's what so damned funny. I checked, all the explosives are there. But they're scattered everywhere, all mixed up with fuses and detonators."

"Who's been in here this afternoon?"

He shrugged. "Who hasn't?"

It was true enough. Everyone had been coming and going there all afternoon and evening, the men for a hundred and one pieces of equipment for the tractor body, the women for food and stores. And, of course, our primitive toilet lay at the farthest end of the tunnel.

"What happened to you, sir?" Joss asked quietly.

I told him, and watched his face tighten till the mouth was a thin white line in the dark face. Joss knew what it meant to be lost on the ice-cap.

"The murderous, cold-blooded she-devil," he said softly. "We'll have to nail her, sir, we'll have to, or God only knows who's next on her list. But – but won't we have to have proof or confession or something? We can't just – "

"I'm going to get both," I said. The bitter anger still dominated my mind to the exclusion of all else. "Right now."

I walked out of the tunnel and across the cabin to where the stewardess was sitting.

"We've overlooked something, Miss Ross," I said abruptly. "The food in your galley on the plane. It might make all the difference between life and death. How much is there?"

"In the galley? Not very much, I'm afraid. Only odds and ends for snacks, if anyone was hungry. It was a night flight, Dr Mason, and they had already had their evening meal."

Followed by a very special brand of coffee, I thought grimly. "Doesn't matter how little it is," I said. "It might be invaluable. I'd like you to come and show me where it is."