For Tess's heart had understood even more clearly than her mind what Lizzie meant by being what isn't. And it had acted before her mind had been able to doubt, and to stop it. In front of the krool's retreating underbelly was a huge and magnificent dragon, and then there were two of them, blasting flame at the hideous eye, which shrivelled and melted and dripped like warm treacle into the snow. The krool reared as high as it could go, a mile into the sky, but the dragons took to the wing and continued their pursuit until it collapsed and doubled back on itself like a monstrous, black pancake.

The two dragons leapt for the skies in a delirium of delight. They were faster, cleverer, more powerful than any creature on earth, and they swooped and soared, chased each other's tails and tumbled in the air in sheer elation. This was the feeling that their premonitions had promised them, the certainty of power beyond human imagination, the sensation of absolute freedom. For all the elements were theirs to enjoy. They were equally at home in water, earth and air, but they were not bound by any of them. They carried the secret of fire within them, and even the great ice wastes all around them could cause them no discomfort. They were the rulers of all they surveyed, and there was no creature on earth that could defeat them.

In the midst of their celebrations, they heard the plane pa.s.sing above them in the clouds. Heard it first, and then saw it, with their infra-red vision.

Just as it saw them. The scanner beeped, warning of a strong signal. Jake sat bolt upright and stared at the screen.

'You got something, Jake?' said Scud.

'Holy G.o.d,' said Jake. 'What the h.e.l.l is that?'

'What is it, Jake, what is it? You got something?'

Hadders sat up and turned around in his seat.

'I've never seen anything like it,' said Jake, his eyes filled with wonder.

'What the h.e.l.l is it, Jake?' Scud yelled.

Jake moved into military mode, sharp and efficient. 'We got hotspots, boys. Two of them. I don't know what they are and I don't know where they came from, but they're like nothing I ever saw before.'

Hadders had left his seat and was standing in the small s.p.a.ce beside Jake, looking over his shoulder at the screen. 'Swing around, Scud,' he said. 'We're losing them.'

'Who's giving the orders around here?' screamed Scud. 'What the h.e.l.l are you doing, standing back there telling me what to do?'

'You should see this, sir. We should get a better look before we go past.'

Scud gritted his teeth and swore, but he dipped his wings and swung around in the tightest circle the plane could handle. 'Come in, base,' he said into the radio mike. 'This is Delta Zero Five, are you reading me?'

General Wolfe was sitting at his desk in Mission Control when one of the technical a.s.sistants called him over to the computer terminal which was receiving Scud Morgan's pictures. 'G.o.d d.a.m.n,' he said. 'What the h.e.l.l is that?'

'd.a.m.ned if I know,' said the aide. 'There's no plane in the world that flies like that.'

The shapes on the screen were descending in rapid circles, leaving a residue of heat in their wake that showed up on the monitor like the tail of a comet. The plane was pa.s.sing above them and moving away again.

'Get on to the guys in that plane,' said Wolfe. 'Tell them to stay above those things and keep sending back pictures.'

'Yes, sir.'

By now there was quite a gathering around the terminal, watching the screens. 'I knew it,' said Wolfe. 'Didn't I tell you, huh? I knew there was something in there.'

CHAPTER NINETEEN.

THE PLANE ABOVE THEIR heads was unsettling, but dragons are not easily intimidated. When they realised that it was not going to go away, they agreed to ignore it and go in search of more krools. They split up, one going east and the other west, flying low enough to be able to see the ground beneath them.

The plane above circled one last time, then followed Kevin. For a while he allowed it to drone along behind him, but then he grew irritated by it, and doubled back on himself, too rapidly for the plane to follow. Then he flew south at top speed for a while, and did not turn back to his original course until he was sure that the skies around him were clear.

Scud Morgan swore. Jake shook his head. Mark Hadders went back to his seat and his book.

A krool in a snowstorm is not easy to find, even for a dragon. Kevin scanned the ground as he flew, but it was only by chance that he came across his second krool. It was sliding southwards across Norway, more slowly now than in the preceding weeks, but still making good progress. It had fed well recently, cutting a great swathe through the forested regions in its path, and had grown to enormous dimensions.

Krools do not reproduce like most of the other creatures of the earth. They don't mate with others of their kind, and they produce neither eggs nor young. When they reach a certain critical ma.s.s, however, they divide, simply split down the middle and become two, like amoebae. Kevin was able to spot this krool from the air because it was in the process of doing just that.

Where it was splitting into two the camouflage of snow was shifting and revealing patches of the glutinous black flesh beneath. Kevin slowed, wheeled round and returned, spitting flame. But by the time he reached it, the krool had become aware of the hot little presence above and glued itself firmly to the ground.

The first krool had been so easy to dispose of that Kevin wasn't prepared for the battle which followed. The krool did nothing, merely sat tight, knowing that as long as it didn't reveal its underneath to the attacker it was almost invulnerable. Almost, but not quite. Kevin came in time after time, throwing flame constantly. Wherever he attacked the krool, it melted into black, oily liquid, but it was so huge that his best efforts made little impression on its bulk.

He stopped for a while, trying to work out a plan. It was tiring, the way he was acting, and he realised that he was using too much energy. If he became exhausted, he would have to rest, and then feed, and when he thought about feeding his mind became filled with pictures of what dragons best like to eat, which is people. And when he thought of people, he could think of only people that he knew, and he wondered if any Switchers before him had experienced the weird sensation of imagining a slap-up meal consisting of their relatives and friends.

To take his mind off these unpleasant thoughts, he returned to the krool and flew up the gradual contour of its body until he reached the highest point. Then he burned away in one spot, calmly and consistently, until he had produced a hollow full of bubbling black liquid like a cauldron. Still he carried on, until at last the heat melted a hole right through the krool and the liquid flowed away on to the ground beneath it. The beast began to convulse, flapping its skirts and heaving its great body so that the snow which covered it flew up in a thick cloud. Kevin hovered in the air and waited until the krool gave a final shudder and lay still.

High above, a satellite had picked up the heat emissions from the battle, and three planes were converging on the spot. But by the time they arrived, Kevin was gone, and their surveillance equipment picked up no signs of life.

But a few hundred miles away, above Greenland, another plane was about to intercept Tess's path. Her infra-red image had just appeared on the aircraft's monitor, and a rapid radio communication had put the crew on to the offensive. Wolfe didn't know what those things were out there, but he wasn't taking any chances. The first heat-seeking missile was armed and ready to go.

Tess's flight path was erratic and unpredictable, and the pilot of the bomber wasn't about to take chances. As soon as he got a clear radar fix, he fired off the missile and swung around out of the area.

Tess had known that the plane was there, but she hadn't expected that it would be able to detect her. She accepted her dragon ability to see objects by the heat they emitted, but she had no idea that there was an equivalent technology available to the military. So, when she picked up the image of the missile snaking towards her, she was completely off guard. If she had been expecting it she might have dodged, since dragons can perform fantastic aerial manoeuvres which no missile could possibly follow. Instead, instinctively, she changed herself into a swallow. The missile swept past, catching her in its current of air and swirling her around in the blizzard. Then, finding itself without a target, it ploughed blindly on, straight into the snow beneath.

The swallow was well clear of the centre of the explosion, but even so, chunks of snow and ice flew up to where she was recovering her balance high above. She flew upwards and away, but in no time at all the blood of the little bird began to freeze. She listened for a moment, and as soon as she was sure that the plane was not returning she Switched back into the warm and fearless form of the dragon.

The monitor in Mission Control slowly cleared and became blank as the heat from the explosion died away. A great cheer went up. General Wolfe leant back in his chair and clasped his hands behind his head in satisfaction. 'Whatever it was, we got it,' he said.

'Uh oh,' said a technician behind him. 'I'm afraid not, sir.'

'What?' Wolfe sat up again. There, on the screen, was the hot spot again, as clear as ever. It was heading east with surprising speed. 'But it disappeared, didn't it?'

'It looked like it did,' said the technician. 'Maybe the heat from the explosion just masked it somehow. It's there now, anyhow.'

It was, and racing back through the snowstorms towards Kevin. He had heard Tess's call and was coming to meet her. From their positions all over the Arctic Circle, the military planes moved in.

It was nearly dark when the two dragons met above the Norwegian Sea, and it was time to call it a day. Their infra-red vision enabled them to see planes overhead, but no kind of vision would enable them to find krools in the dark. Kevin wanted to stay a dragon, but Tess had learnt that they were not as invisible as they had believed, and insisted on the safety of polar bears. Kevin capitulated. They dug in quickly and slept straight away, curled closely together for comfort.

As soon as the sun came up the next morning, the two hot spots were picked up on the monitors of a surveillance plane. They didn't appear gradually, as a plane does when it starts its engines and warms up, and they neither taxied to a runway nor rose vertically. One moment there was nothing on the infrared screens above, and then there were two large, hot objects flying off at impossible speed in different directions.

This time, Tess and Kevin had a plan. It was a dangerous plan and would require all their courage and all their wits but, if it worked, it would be a brilliant way to get rid of the krools. All they had to do was to find them.

They had decided to fly low, so low that a krool would appear to them as a patch of slowly-rising ground which would then fall away again. In the middle of a blizzard such flying required steel nerves and lightening fast reactions, but the dragon has both, even at the speed of a jet plane.

When they had talked in the early hours of the morning, Tess and Kevin had agreed that there must be a vanguard of krools along the same lat.i.tude as the first ones they had found, to account for the even progress of the blizzards that preceded them. So the dragons flew in straight lines, due east and due west from where they had started. Several times in the first hour, Tess slowed and circled to examine a suspicious slope in the ground, but each time it was a false alarm. Above her the planes criss-crossed continuously, and she had already out-foxed three missiles before she found her first krool. As soon as she was certain of it, she rose some distance into the clouds above and circled steadily, waiting. Before long she saw the tell-tale heat of the approaching plane and heard its engine. As soon as it was within range, it launched its missile. Tess dived at full speed towards the unsuspecting krool. The missile spun after her, coming closer to her tail, until at the last minute, she Switched as she had done before and swung out of the way. It worked. The garnered momentum of the dragon dive flung the little bird out into the blizzard at terrifying speed, and away from the explosion. A few bits of exploded krool reached her as she shot through the air, but she was too busy trying to gain control of her dizzying flight to be concerned about them.

In Mission Control, the observers watched the clearing screen in tense silence. Then someone said: 'We got one this time.'

There was no cheer. This had happened before. 'Don't count your chickens,' said Wolfe, then groaned as the hot spot reappeared and resumed its eastward flight.

On the other side of Greenland, heading west, Kevin was playing the same game, with slightly more success. He had discovered a better way of finding his prey.

A krool crossing land leaves a distinct trail behind it where it has cut a mile-wide path through the vegetation and left nothing but a clean sweep of powdered snow, ice and rock. Kevin happened to notice this when he found his first krool of the day, and after that he stopped looking for their convex forms and searched instead for abrupt tree-lines or abnormally smooth stretches of snow. The method served him well. He found krool after krool, and each time he hovered above them and waited until the military arrived.

As the day wore on, General Wolfe grew increasingly exasperated. The events of the day were beginning to send shivers down his spine. It was becoming clearer all the time that whatever those things were, they were playing games with him. The phone was ringing from Washington a little too often and the questions were becoming embarra.s.sing.

But the strangest thing of all was that whatever was happening out there was having the desired effect on the weather. Already the blizzards were dying out and clouds were disappearing from large areas that had previously been covered. In southern England and Ireland, he was told, the sun was shining and the snow was beginning to melt.

It was just in time for Lizzie. For the first few days of the blizzards, Mr Quigley had been extremely helpful. He had come every day with whatever supplies Lizzie needed, and he and his daughter had shovelled the snow away from her door and made paths to Nancy's shed and the henhouse. But then, one day, he had come and told her that he had sold all his stock and managed to get a pa.s.sage for himself and his family on a ferry to Cyprus, and he could not let the opportunity pa.s.s. He had brought her provisions for a fortnight and a hundredweight of rock salt to help against the snow, but beyond that he could do nothing more for her.

When the daily digging became too much for her, Lizzie brought Nancy and the hens into the house and let them have the use of the scullery. The mains water had long since frozen tight, so she filled the bath and the sink and a few old milk churns with snow. Then she brought in as many logs as she could stack in the hall, and closed the doors. She was dug in like an Arctic creature in her little snow-hole of a cottage, and was forgotten by the world.

The drifts rose until they covered the downstairs windows, and, since the power lines were down over half the country, Lizzie moved around in the dim light of the fire, saving her candles for emergencies. The first thing to run out was the oats she fed to Nancy and the chickens, and she had to start sharing her own rations with them. Then water began to get scarce. The plug in the bath had proved useless, and the snow which Lizzie had gathered so laboriously ran away as soon as it melted. She was reduced to sc.r.a.ping snow from the insides of the drifts outside the windows and melting it over the fire, and anyone who has ever tried this will know that it is a lot of work for very little return. By the time the sun appeared, Lizzie was exhausted, dispirited, and almost down to the last of her provisions.

If it hadn't been for the cats, she would probably not have known the snow had stopped until the next day. Her kitchen was as dark as a bas.e.m.e.nt with the windows all covered in drifts, but it was too cold to sit upstairs where there was still light. The cats, however, went up and down quite often during the day to use the litter tray that Lizzie had set up in the spare room for them as soon as they could no longer get out.

It was when Moppet failed to return from one of these visits that Lizzie went upstairs to investigate and found him curled up on the windowsill in the sunshine. For the first time since Tess and Kevin had left her house, Lizzie's stiff old back straightened up. She went to the window, prised it open, and called out to the sky: 'You did it, you little horrors! You made it!'

CHAPTER TWENTY.

BACK AT THE EDGE of the Arctic Circle, the dragons were still at work. Tess had eventually discovered Kevin's method of detection for herself, and was making up for lost time.

In Mission Control, General Wolfe was getting fed up with throwing missiles at infra-red ghosts, but he had discovered that there was little else he could do. He had found volunteers to go in for close combat in fighter planes armed with machine guns and close-range missiles, but they had flown back bewildered. As soon as they came anywhere near to visual range, their targets disappeared. Simply vanished without trace.

Wolfe called them back. With outward confidence and inward despair, he continued with the missile attacks.

Tess and Kevin were in a mood of high exhilaration. They were living by the skin of their teeth, dodging death one minute and tempting it the next. As a result, life had never seemed better or more precious.

And they were winning. Their phenomenal speed had taken them around the globe to meet again on the other side above Canada, where they played aerial tag and leapfrog together for a few minutes before turning round and starting back the way they had come, to pick off the krools they had missed.

Wolfe followed their progress on radar and infrared. He now knew that he was playing into their hands in some way, but he also knew that the snowstorms were abating. He didn't know how he was going to explain it, but he was sure of one thing. He was going to take all the credit that was on offer when the time came.

The one in the west was circling again. 'Let him have it,' he said.

Fast as the dragons were, they couldn't make it back around the globe before nightfall. They could call to each other, though, and they did, before they came to land and settled as polar bears into their separate dug-outs for the night.

Tess slept fitfully, dreaming bear dreams and dragon dreams, and terrible dreams of Kevin trapped in the form of some awful creature for the rest of his life. A single bear produces very much less heat than two curled up together, and she woke before dawn, stiff and sore with the cold. She knew that the only way to get warm was to get moving, so she crawled out of the tunnel and was amazed to find herself standing in the middle of clearly visible snowfields, stretching away in all directions, glowing in the light of the stars which shone out of a cloudless sky.

A plane pa.s.sed low over her head, blinking a single, white light. Tess shook her damp coat and began to trot northward.

In Mission Control, General Wolfe was popping caffeine pills to keep himself awake. The meteorological satellites were beaming down gratifying pictures of the cloud formations. A few isolated blizzards were still stretching southward like thick fingers, but otherwise the area below the line of seventy degrees lat.i.tude was clear.

But Wolfe knew that those things, whatever they were, would return in the daylight. He had spent most of the night in a fury of injured pride, and he wasn't about to give up. There were all kinds of theories buzzing around. Some said the hot spots were Iraqi war machines, developed for the purpose of freezing out the Northern Hemisphere and crippling the American and European economies. Others said they were UFOs making a bid to colonise the planet. Wolfe was willing to believe that they came from outer s.p.a.ce, but nothing that had happened had succeeded in convincing him that they were not living beings of some kind. He hadn't forgotten those two tapes.

As Tess warmed up she began to make plans. The blizzards had died down, she knew, because of the krools she and Kevin had killed, but there would surely be others closer to the Pole which would need her attention. Even in the dark, however, she was reluctant to become a dragon now that the cover of clouds had gone, just in case some low-flying plane might get a sight of her in the starlight. So she Switched instead to a Canadian goose, and began to fly steadily north.

She was right about the krools. What she didn't know, however, was that they were no longer a danger. Apart from the unknown enemy in the skies, they were under increasing threat from their greatest enemy, the sun. Only in large numbers can krools be certain of producing sufficient freezing clouds to keep them covered and safe. A single krool cloud can be dispersed by warm winds and leave its maker helpless, melting in the sun. Already the second and third line of them were in rapid retreat, and the rearguard had retraced their tracks and slithered back into their icy beds.

Kevin woke at dawn, and the first thing he knew was that it was the day before his birthday. He had one more day and one more night.

He emerged from his den and stretched. It was still snowing, but the snow was softer that it had been, and kinder. He was feeling fresh, and ready for another day's action, but before that he wanted to have a look around, and he knew exactly how he was going to do it. In the blink of an eye he was a dragon again, moving rapidly up towards the top of the clouds.

The air force was waiting for him, and a pa.s.sing plane let off a missile as he rose towards it, but he Switched and dodged it easily. It exploded beneath him, not far from his snow-hole. When he recovered his equilibrium, he Switched again, and set off at high speed towards the Pole. He flew so fast that he soon outdistanced the planes behind him, and by doubling and zig-zagging as he went, he was able to confuse the controllers on the ground until at last he found that he had a clear sky above him. Rapidly, he dropped a couple of hundred feet so that he could give himself the momentum he needed, then he launched himself like a rocket, straight up through the clouds and into the air above them.

It was similar to the way a spaniel will jump up above the long gra.s.s to get a look around, except that Kevin went up almost as far as the stratosphere. From there he could clearly see the pattern of clouds beneath, which told him the exact locations of the outlying krools. It took him scarcely a second to take it all in, and then he was dropping again, like a monstrous hawk plummeting down through the sky.

In front of the monitors in Mission Control, a dozen mouths dropped open in disbelief as radar relayed the astonishing feat.

'What the h.e.l.l,' said General Wolfe, 'are we dealing with?'

Just across the Arctic Circle from Kevin, Tess had reached the safety of clouds and Switched. Kevin had been calling periodically throughout the morning and was delighted at last to get a reply. He called again, relaying his information about the whereabouts of the krools, and the two dragons set about finishing them off.

It was easy now. All they had to do was to sweep down along the fingers of cloud until they found the krools. After a while, Mission Control began to understand the pattern, and quite often the dragons found that the planes were already in position even before they arrived.

By late afternoon, Tess and Kevin had located every krool that lay outside the line of seventy degrees lat.i.tude. They met directly above the North Pole, where night had already fallen, to celebrate and discuss tactics. Kevin was full of the joys of victory, and was in favour of carrying on, but Tess wanted to stop and talk to him. She was as excited as he was, but for a different reason. For a while they argued in the air, until they became angry and began to burn each other's noses and ears with jets of flame, which sobered them up a bit. In the end, Kevin relented and they sprinted away from the planes gathering above them until they had left them behind. Then they geared down to geese in order to put the enemy off their tracks and flew on for a while. Finally, when the skies were clear of planes, they landed in a strange amphitheatre of ice in the middle of the Greenland Sea.

'Phew,' said Kevin, when they stood face to face at last. 'It's cold.'

'Yes,' said Tess. 'So we have to talk fast.'

'What's so important, anyway?'

'This,' said Tess. 'We've got the krools on the run, right?'

'Well, we've knocked most of them out, anyway.'

'Right. And I knocked out two today up in Northern Greenland that were definitely going backwards.'

'Did you?'

'Yes. Going at a h.e.l.l of a speed, too. So listen. Maybe the job is finished, you know? And even if it isn't, I could always finish it off on my own if I had to.'

'But why should you?'

'Because maybe you can still have the chance to be what you want to be.'

'But there's not much choice up here, is there? Anyway, I quite like being a dragon.'