"Means nothing," Miss LeGarde assured her cheerfully. "Neither do I. It's just that we're both frozen stiff. . . . And how did you survive the night, Mrs Dansby-Gregg?"

"As you say, I survived." Mrs Dansby-Gregg smiled thinly. "As Dr Mason observed last night, this is not the Ritz.. . . That coffee smells delicious. Bring me a cup over, Fleming, will you?"

I picked up one of the cups Jackstraw had poured out and took it across to the young German girl who was struggling to unzip her sleeping-bag with her one good arm. Her embarrassment and discomfort were obvious, but I knew I'd no option, the time to stop this nonsense was before ever it had a chance to start.

"You stay where you are, young lady, and drink this." She took the cup reluctantly, and I turned away. "You've surely forgotten, Mrs Dansby-Gregg, that Helene has a broken collar-bone?"

The expression on her face made it quite obvious that she hadn't forgotten, but she was no fool. The gossip columnists would murder her for this, if they got hold of it. In her circle, an outward if meaningless conformity to the accepted mores and virtues of the day was a sine qua non: the knife between the ribs was permitted, but only to the accompaniment of the well-bred smile.

"I'm so sorry," she said sweetly. "I'd quite forgotten, of course." Her eyes were cold and hard, and I knew I had an enemy. That didn't worry me, but I found the very triviality of the whole thing irritating beyond measure when there were so many other and vastly more important things to talk about. But less than thirty seconds later we had forgotten all about it, even, I am sure, Mrs Dansby-Gregg herself.

I was just handing Marie LeGarde a cup when someone screamed. It wasn't really loud, I suppose, but in that confined space it had a peculiarly piercing and startling quality. Marie LeGarde's arm jerked violently and the scalding contents of the coffee-cup were emptied over my bare hand.

I hardly noticed the pain. It was Margaret Ross, the young stewardess, who had screamed, and she was now kneeling, half in and half out of her sleeping-bag, one rigidly spread-fingered hand stretched out at arm's length before her, the other clasped over her mouth as she stared down at the figure lying near her on the floor. I pushed her to one side and sank on to my own knees.

In that bitter cold it was impossible to be any way sure, but I felt reasonably certain that the young pilot had been dead for several hours. I knelt there for a long time, just looking down at him, and when I finally rose to my feet I did so like an old man, a defeated old man, and I felt as cold, almost, as the dead man lying there. Everyone was wide awake now, everyone staring at me, the eyes of nearly all of them reflecting the superstitious horror which the presence of sudden and unexpected death brings to those who are unaccustomed to it. It was Johnny Zagero who broke the silence.

"He's dead, isn't he, Dr Mason?" His low voice sounded a little husky. "That head injury – " His voice trailed off.

"Cerebral haemorrhage," I said quietly, "as far as I can tell."

I lied to him. There was no shadow of doubt in my mind as to the cause of death. Murder. The young boy had been ruthlessly, cold-bloodedly murdered: lying there unconscious, gravely injured and with his hands strapped helplessly to his sides, he had been smothered as easily, as surely, as one might smother a very little child.

We buried him out on the ice-cap, not fifty yards from the place where he had died. Bringing his stiffened body out of the hatch was a grisly job, but we managed it and laid him on the snow while we sawed out a shallow grave for him in the light of one of our torches. It was impossible to dig it out: that frozen ringing surface turned shovel blades as would a bar of iron: even at eighteen inches, the impacted ntvt of snow and ice defied the serrated spearpoints of our special snow saws. But it was deep enough and within a few hours the eternal ice-drift would have smoothed its blanket across the grave, and we would never be able to find it again. The Reverend Joseph Smallwood murmured some sort of burial service over the grave but his teeth chattered so violently in the cold and his voice was so low and indistinct and hurried that I could hardly catch a word of it. I thought wryly that heavenly forgiveness for this indecent haste was unlikely to be withheld: by all odds it must have been by far the coldest funeral service that Mr Smallwood had ever conducted.

Back in the cabin, breakfast was a sketchy and silent affair. Even in the steadily rising warmth, the melancholy gloom was an almost palpable blanket under the dripping ceiling. Hardly anybody said anything, hardly anybody ate anything. Margaret Ross ate nothing, and when she finally set down her coffee-cup, the contents had scarcely been touched.

You're overdoing it, my dear, I thought viciously, you're carrying the grief-stricken act just a little too far: a little longer, and even the others will start wondering – and they have no suspicions at all, you damned inhuman little murderess.

For I had no suspicions either – only certainty. There was no doubt in my mind at all but that she had smothered the young pilot. She' was only slightly built – but then it would have required only slight strength. Lashed to the cot as he had been, he wouldn't even have been able to drum his heels as he had died. I could feel my flesh crawl at the very thought.

She had killed him, just as she had broken the radio and doped the passengers. He had been killed, obviously, to keep him from talking – about what, I couldn't even begin to guess, any more than I could guess the reason for the destruction of the radio, except that she clearly did not want the news of the crash broadcast to the outer world. But why in the world destroy the radio in the first place, surely she must have known how essential it was for survival? But then, after all, how was she even to have guessed that: she might well have thought that we had big fast tractors that could have whipped them down to the coast in a matter of a couple of days. For that matter, she might have thought she was a great deal nearer the coast than we really were -it was impossible, surely, that she had genuinely imagined that we were in Iceland. Or was it?

My thoughts were spinning now in an unbreakable circle. I knew I was getting nowhere, couldn't possibly get anywhere without some fresh information. As it was, I was only confusing myself the more with the passing of every moment. I gave it up then, promising myself that from now on I would watch her every possible minute of the day. I looked at her again, covertly, and she was staring vacantly at one of the glowing embers of the stove. Planning her next move, no doubt, planning it as cleverly as the last: asking me last night about the pilot's chances of survival, doubtless to decide whether he would have to be killed or could safely be left to die, had been clever enough, but insisting on sleeping next to the man she had meant to kill had been nothing short of brilliant. On that account alone no one would ever suspect her, even if the fact that it had been murder became known. And it wouldn't: I intended keeping that to myself. Or did she suspect I suspected? Heaven only knew. All I knew was that she must be playing for tremendous stakes. Or that she was mad.

It was just after eleven o'clock. Joss and Jackstraw were in a corner by themselves, stripping down the smashed transmitter, while the rest were grouped in a large semi-circle round the stove. They looked wan and sickly and were sitting very still indeed. They looked unwell because the first greyness of the noon twilight was stealing through our rimed skylights and it did unflattering things to any complexion: and they sat so still because I had just explained to them in detail exactly what their situation was, and they didn't like it one little bit. Neither did I.