I never doubted him. I knew he'd do it in an instant. I gave him our position, he asked for another map, asked Jackstraw to mark our position on the second, and compared the two.

"They coincide," he nodded. "Fortunately for you." He studied the map briefly, then looked at Corazzini. "The Kangalak fjord, undoubtedly, at the foot of the Kangalak glacier. Approximately—"

"The Kangalak fjord," I interrupted. My voice was bitter. "Why the hell didn't you land there in the first place and save us all this?"

"The plane captain deserved to die," Smallwood said obliquely. His smile was wintry. "I had instructed him to put down on the coast just north of the fjord where our—ah—friends had reconnoitred a section of the ice-cap, three miles long and absolutely flat, that is the equal of the finest runway in Europe or America, and it wasn't until I saw the altimeter reading just before the crash that I realised he had deceived me." He made an impatient gesture and turned to Corazzini. "We waste time. Approximately sixty miles, you would say?"

Corazzini examined the map. "Yes, about that."

"So, come then, on our way."

"Leaving us here to starve and die of cold, I suppose?" I said bitterly.

"What becomes of you no longer concerns me," Smallwood said indifferently. Already, in a matter of minutes, it had become almost impossible to think of him, to remember him as the meek retiring minister we had known. "It is possible, however, that you might be foolish enough to take advantage of the cover of snow and darkness to run after us, waylay and try to overcome us. You might even succeed, even though unarmed. We must immobilise you, temporarily."

"Or permanently," Zagero said softly.

"Only fools kill wantonly and unnecessarily. Fortunately—for you—it is not necessary for my plans that you die. Corazzini, bring some rope from the sled. There's plenty of cord there. Tie their feet only. With their numbed hands it will take them an hour to undo their bonds: we will be well on our way by then." He moved his gun gently from side to side. "Sit in the snow. All of you."

There was nothing for it but to do as we were told. We sat down and watched Corazzini bring a hank of cord from the sled. He looked at Smallwood, and Smallwood nodded at me.

"Dr Mason first."

Corazzini gave his gun to Smallwood—they missed nothing, that pair, not even the remote possibility that one of us might try to snatch Corazzini's gun—and advanced on me. He knelt and had taken a couple of turns round my ankles when the truth struck me with the suddenness, the shocking impact of a physical blow. I sent Corazzini staggering with a violent shove and leapt to my feet.

"No!" My voice was hoarse, savage. "By God, you're not going to tie me up, Smallwood!"

"Sit down, Mason!" His voice was hard, whip-like, and the light from the tractor cabin was enough for me to see the rock-like pistol barrel centred between my eyes. I ignored it completely.

"Jackstraw!" I shouted. "Zagero, Levin, Brewster! On your feet if you want to live. He's only got one gun. If he starts firing at any of us, the rest go for him and get him—he can't possibly get us all. Margaret, Helene, Mrs Dansby-Gregg-first shot that's fired, run off into the darkness—and stay there!"

"Have you gone crackers, Doc?" The words came from an astonished Zagero, but for all that something namelessly urgent and compelling in my voice had got him to his feet, and he was bent forward, crouched like a great cat, ready to launch himself at Smallwood. "Want to get us all killed?"

"That's just what I don't want." I could feel my spine, the back of my neck cold with a cold that was not of the Arctic, and my legs were trembling. "Going to tie us up and leave us here? Is he hell! Why do you think he told us of the trawler, its position, the submarine and all the rest of it? I'll tell you why—because he knew it was safe, because he'd made up his mind that none of us would ever live to tell of these things." I was rattling the words out with machine-gun rapidity, desperate with the need to convince the others of what I was saying before it was too late: and my eyes never left the gun in Smallwood's hand.

"But—"

"No 'buts'," I interrupted harshly. "Smallwood knows that Hillcrest will be coming through here this afternoon. If we're still here—and alive—first thing we'd tell him would be Smallwood's course, speed, approximate position and destination. Within an hour the Kangalak glacier would be sealed, within an hour bombers from the Triton would have blasted him off the face of the glacier. Tie us up? Sure—and then he and Corazzini would shoot us at their leisure while we flopped around like birds with broken wings."

Conviction was immediate and complete. I couldn't see the faces of the others, but the fractional lowering of Smallwood's gun was enough to tell me.

"I underestimated you, Dr Mason," he admitted softly. His voice was devoid of all trace of anger. "But you almost died there."

"What's five minutes more or less?" I asked, and Smallwood nodded absently. He was already working out an alternative solution.

"You—you inhuman monster!" Senator Brewster's voice was shaking with fear or anger or both. "You were going to tie us up and butcher us like—like—" Words failed him for a moment, then he whispered: "You must be mad, Smallwood, stark raving mad."

"He's not in the slightest," Zagero said quietly. "Not mad. Just bad. But it's kind of hard to tell the difference at times. Figured out our next jolly little scheme, Smallwood?"

"Yes. As Dr Mason says, we can't possibly dispose of all of you inside a couple of seconds, which is all the time it would take for one—probably more—of you to reach the cover of the snow and darkness." He nodded towards the tractor sled, lifted his high collar against the snow and biting wind. "I think you had better ride a little way with us."

And ride with them we did for the thirty longest miles I have ever driven, for nine hours that had no end. A relatively short distance, but this eternity of time to cover it: partly because of the sastrugi, partly because of the increasingly long stretches of soft snow, but mainly because of the weather, which was deteriorating rapidly. The wind had now risen to something better than thirty miles an hour, it carried with it a blinding wall of flying ice-filled drift, and, even though it was directly behind us, it made things troublesome for the driver. For all the others except Smallwood it made the conditions intolerable: had the temperature been what it was only twenty-four hours previously, none of us, I am sure, would have survived that trip.

I would have thought that with either Smallwood or Corazzini driving and the other navigating from the dog-sled we would have had a chance, slender though it might be, to overpower them or at least make good our escape. But Smallwood never offered even a shadow of a chance of either. Corazzini drove all the time, with the radio direction finder headphones clamped to his ears, so that compass navigation became an inaccurate superfluity. Smallwood sat alone in the back of the tractor cabin, his gun unwaveringly trained on the rest of us who were crammed aboard the big tractor sled, ten feet to the rear of him: when the snow eventually became too heavy he stopped the tractor, detached the portable searchlight and mounted it, facing aft, in the rear of the tractor cabin; this had the double advantage of illuminating us so that he could clearly see us even through the drift and making certain that none of us tried to drop off the sled, and of blinding us so that we were quite unable to see what he was doing, even to see whether he was watching us at all. It was frustrating, maddening. And, for good measure and to prevent any desperate attempt at escape in the occasionally blinding flurries of snow, he brought Margaret and Helene up into the cabin and bound their hands: they were the surety for our good conduct.

That left eight of us on the tractor sled, Theodore Mahler and Marie LeGarde stretched out in the middle, three of us sitting on each side. Almost immediately after we had moved off and pulled a pair of tarpaulins over ourselves for what meagre shelter they could afford, Jackstraw leaned across and tapped me on the shoulder with something held in his hand. I reached up and took it from him.

"Corazzini's wallet,1 he said softly. For all the chance of his being overheard by either Smallwood or Corazzini above the roar of the engine and the voice of the gale, he could have shouted out the words. "Fell from his pocket when Zagero knocked him down. He didn't see it go, but I did—sat on top of it while Smallwood told us to squat in the snow."

I stripped off my gloves, opened the wallet and examined its contents in the light of the torch Jackstraw had also passed across—a torch with the beam carefully hooded and screened to prevent the slightest chink of light escaping from under the tarpaulin: at this time, Smallwood had not yet switched on the searchlight.

The wallet provided us with that last proof of the thoroughness, the meticulous care with which these two men had provided themselves with false but utterly convincing identities: I knew that whatever Corazzini's name was it wasn't the one he had given himself, but, had I not known, the 'N.C." stamped on the hand-tooled morocco, the visiting cards with the inscribed 'Nicholas Corazzini' above the name and address of the Indiana head office of the Global Tractor Company, and the leather-backed fold of American Express cheques, each one already signed 'N. R. Corazzini' in its top left-hand corner, would have carried complete conviction.

And, too late, the wallet also presented us, obliquely but beyond all doubt, with the reason for many things, ranging from the purpose of the crash-landing of the plane to the explanation of why I had been knocked on the head the night before last: inside the bill-fold compartment was the newspaper cutting which I had first found on the dead body of Colonel Harrison. I read it aloud, slowly, with infinite chagrin.

The account was brief. That it concerned that dreadful disaster in Elizabeth, New Jersey, where a commuters' train had plunged through an opened span of the bridge into the waters of Newark Bay, drowning dozens of the passengers aboard, I already knew from the quick glance I had had at the cutting in the plane. But, as I had also gathered in the plane, this was a follow-up story and the reporter wasted little time on the appalling details: his interest lay in another direction entirely. It was 'reliably reported', he said, that the train had been carrying an army courier: that he was one of the forty who had died: and that he had been carrying a 'super-secret guided missile mechanism'.

That was all the cutting said, but it was enough, and more than enough. It didn't say whether the mechanism had been lost or not, it most certainly never even suggested that there was any connection between the presence of the mechanism aboard the train and the reasons for the crash. It didn't have to, the cheek-by-jowl contiguity of the two items made the reader's own horrifying conclusions inevitable. From the silence that stretched out after I had read out the last words, I knew that the others were lost in the same staggering speculations as myself. It was Jackstraw who finally broke this silence, his voice abnormally matter-of-fact.

"Well, we know now why you were knocked on the head."

"Knocked on the head?" Zagero took him up. "What do you—"

"Night before last," I interrupted. "When I told you I'd walked into a lamp-post." I told them all about the finding of the cutting and its subsequent loss.

"Would it have made all that difference even if you had read it?" Zagero asked. "I mean—"

"Of course it would!" My voice was harsh, savage almost, but the savagery was directed against myself, my own stupidity. "The fact of finding a cutting about a fatal crash which occurred in strange unexplained circumstances on the person of a man who had just died in a fatal crash in equally strange and unexplained circumstances would have made even me suspicious. When I heard from Hillcrest that something highly secret was being carried aboard the plane, the parallel would have been even more glaringly obvious, especially as the cutting was found on the man—an army officer—who was almost certainly the courier, the carrier of this secret. Anything larger than a match-box in the luggage the passengers were carrying I'd have ripped open and examined, radio and tape-recorder included. Smallwood knew it. He didn't know what was in the cutting, but he—or Corazzini—knew it was a cutting and they were taking no chances at all."

"You weren't to know this," Levin said soothingly. "It's not your fault—"

"Of course it's my fault," I said wearily. "All my fault. I don't even know how to start apologising. You first, Zagero, I suppose, you and Solly Levin, for tying you—"

"Forget it." Zagero was curt but friendly. "We're just as bad -all of us. All the facts that mattered were as available to us as they were to you—and we made no better use of them: less, if anything." In the tiny glow from the torch I could see him shaking his head. "Lordy, lordy, but ain't it easy to understand everything when it's too late. Easy enough to understand now why we crashed in the middle of nowhere—the plane captain must have been in on it, he must have known that the mechanism was aboard and thought it important enough to put the passengers' lives second and crash-land in the middle of the ice-plateau, where Smallwood could never reach the coast."

"Not knowing that I was there waiting to oblige Smallwood," I said bitterly. I shook my head in turn. "It's obvious now, all too obvious. How Corazzini damaged his hand in the shack—not by saving or trying to save the radio but by accelerating its fall after he'd pushed the hinges in. How and why he lost the toss and had to sleep on the floor—to give him a chance to smother the second officer."

"What you might call a good loser," Zagero said grimly. Then he gave a short laugh. "Remember when we buried the second officer? I wonder what Smallwood's burial service would have sounded like if we'd really been close enough to hear?"

"I missed that," I nodded. "I missed the suggestion you made inside the plane that we should bury the murdered men—if you had been guilty you'd never have dared make that suggestion for then the way these men died would almost certainly have been discovered."

"You missed it," Zagero said feelingly. "How about me—/said it, and I never even thought of it till now." He snorted. "Boy, am I disgusted with myself. As far as I can see the only thing I knew that you didn't was that Corazzini clouted our friend Smallwood back in the pass there simply in order to throw suspicion on me: but, then, I knew that even trying to tell you that would have been crazy."

There was a long moment's silence, while we listened to the rise and fall of the Citroen's exhaust note in the gusting, strengthening wind, then Solly Levin spoke.

The plane," he said. "The fire—how come?"

"There was enough high-octane fuel in its tanks to take Hillcrest's Sno-Cat a couple of thousand miles," I explained. "If Hillcrest's tanks had been empty when he arrived back at base and if he'd found out right away that the spare fuel in the tunnel had been doctored—well, it wouldn't have taken him long to siphon out the stuff in the plane. So, no plane."

The silence this time was even longer, then Zagero cleared his throat, as if uncertain how to begin.

"Seeing explanations are in the air—well, I guess it's time we made one too." Zagero, to my astonishment, sounded almost embarrassed. "It's about the phony conduct of that phony character to your left, Doc, one Solly Levin. We'd plenty of time to talk about it when we were lashed to this damned sledge all of last night and—"

"Come to the point," I interrupted impatiently.

"Sorry." He leaned across to Solly Levin. "Want I should make a formal introduction, Pop?"