She stared down the plane, her eyes wide with horror, her lips moving as if to speak, but no sound came.

"They got him too,'I repeated. "Just as they got the captain. Just as they got the second officer – and the flight engineer."

"They?" she whispered. "They?"

"Whoever it was. I only know it wasn't you."

"No," she whispered. Again she shuddered, even more uncontrollably than before, and I tightened my arm round her. "I'm frightened, Dr Mason. I'm frightened."

"There's nothing – " I'd started off to say there was nothing to be frightened of, before I realised the idiocy of the words. With a ruthless and unknown murderer among us, there was everything in the world to be frightened of. I was scared myself: but admitting that to this youngster wasn't likely to help her morale any. So I started talking, telling her of all the things we had found out, of the suspicions we had and of what had happened to me, and when I finished she looked at me and said: "But why was I taken into the wireless cabin? I must have been, mustn't I?"

"You must have been," I agreed. "Why? Probably so that someone could turn a gun on you and threaten to kill you if the second officer – Jimmy Waterman, you called him, wasn't it -didn't play ball. Why else?"

"Why else?" she echoed. She gazed at me, the wide brown eyes never leaving mine, and then I could see the slow fear touching them again and she whispered: "And who else?"

"How do you mean 'Who else'?"

"Can't you see? If someone had a gun on Jimmy Waterman, someone else must have had one on the pilots. You can see yourself that no one could cover both places at the same time. But Captain Johnson must have been doing exactly as he was told, just as Jimmy was."

It was so glaringly obvious that a child could have seen it: it was so glaringly obvious that I'd missed it altogether. Of course there must have been two of them, how else would it have been possible to force the entire crew to do as they were ordered? Good heavens, this was twice as bad, ten times as bad as it had been previously. Nine men and women back there in the cabin, and two of them killers, ruthless merciless killers who would surely kill again, at the drop of a hat, as the needs of the moment demanded. And I couldn't even begin to guess the identity of either of them.

"You're right, of course, Miss Ross," I forced myself to speak calmly, matter-of-factly. "It was blind of me, I should have known." I remembered how the bullet had passed clear through the man in the back seat. "I did know, but I couldn't add one and one. Colonel Harrison and Captain Johnson were killed by different guns – the one by a heavy carrying weapon, like a Colt or a Luger, the other by a less powerful, a lighter weapon, like something a woman might have used."

I broke off abruptly. A woman's gun! Why not a woman using it? Why not even this girl by my side? It could have been her accomplice that had followed me out to the plane earlier in the evening, and it would fit in beautifully with the facts. . . . No, it wouldn't, faints couldn't be faked. But perhaps– "A woman's gun?" I might have spoken my thoughts aloud, so perfectly had she understood. "Perhaps even me – or should I say perhaps still me?" Her voice was unnaturally calm. "Goodness only knows I can't blame you. If I were you, I'd suspect everyone too."

She pulled the glove and mitten off her left hand, took the gleaming ring off her third finger and passed it across to me. I examined it blankly in the light of my torch, then bent forward as I caught sight of the tiny inscription on the inside of the gold band: "J. W.-M. R. Sept. 28,1958'. I looked up at her and she nodded, her face numb and stricken.

"Jimmy and I got engaged two months ago. This was my last flight as a stewardess – we were being married at Christmas." She snatched the ring from me, thrust it back on her finger with a shaking hand and when she turned to me again the tears were brimming over in her eyes. "Now do you trust me?" she sobbed. "Now do you trust me?"

For the first time in almost twenty-four hours I acted sensibly -1 closed my mouth tightly and kept it that way. I didn't even bother reviewing her strange behaviour after the crash and in the cabin, I knew instinctively that this accounted for everything: I just sat there silently watching her staring straight ahead, her fists clenched and tears rolling down her cheeks, and when she suddenly crumpled and buried her face in her hands and I reached out and pulled her towards me she made no resistance, just turned, crushed her face into the caribou fur of my parka and cried as if her heart was breaking: and I suppose it was.

I suppose, too, that the moment when a man hears that a girl's fiance* has died only that day is the last moment that that man should ever begin to fall in love with her, but I'm afraid that's just how it was. The emotions are no respecters of the niceties, the proprieties and decencies of this life, and, just then, I was clearly aware that mine were stirred as they hadn't been since that dreadful day, four years ago, when my wife, a bride of only three months, had been killed in a car smash and I had given up medicine, returned to my first great love, geology, completed the B.Sc. course that had been interrupted by the outbreak of World War Two and taken to wandering wherever work, new surroundings and an opportunity to forget the past had presented themselves. Why, when I gazed down at that small dark head pressed so deeply into the fur of my coat, I should have felt my heart turn over I didn't know. For all her wonderful brown eyes she had no pretensions to beauty and I knew nothing whatsoever about her. Perhaps it was just a natural reaction from my earlier antipathy: perhaps it was pity for her loss, for what I had so cruelly done to her, for having so exposed her to danger – whoever knew that I knew too much would soon know that she knew it also: or perhaps it was just because she was so defenceless and vulnerable, so ridiculously small and lost in Joss's big parka. And then I caught myself trying to work out the reasons and I gave it up: I hadn't been married long, but long enough to know that the heart has its own reasons which even the acutest mind couldn't begin to suspect.

By and by the sobbing subsided and she straightened, hiding from me what must have been a very badly tear-stained face.

"I'm sorry," she murmured. "And thank you very much."

"My crying shoulder." I patted it with my right hand. "For my friends. The other one's for my patients."

"For that, too, but I didn't mean that. Just for not saying how sorry you were for me, or patting me or saying 'Now, now' or anything like that. I -1 couldn't have stood it." She finished wiping her face with the palm of her mitten, looked up at me with brown eyes still swimming in tears and I felt my heart turn over again. "Where do we go from here, Dr Mason?"

"Back to the cabin."

"I didn't mean that."

"I know. What am I to say? I'm completely at a loss. A hundred questions, and never an answer to one of them."

"And I don't even know all the questions, yet," she murmured. "It's only five minutes since I even knew that it wasn't an accident." She shook her head incredulously. "Who ever heard of a civilian airliner being forced down at pistol point?"

"I did. On the radio, just over a month ago. In Cuba – some of Fidel Castro's rebels forced a Viscount to crash land. Only they picked an even worse spot than this -1 think there were only one or two survivors. Maybe that's where our friends back in the cabin got the idea from. I shouldn't be surprised."

She wasn't even listening, her mind was already off on another track.

"Why – why did they kill Colonel Harrison?"

I shrugged. "Maybe he had a high resistance to Mickey Finns.

Maybe he saw too much, or knew too much. Or both."