Presently they came to a large double door. The Doctor tapped in a code on a keypad next to the doors and they opened.

Kerstin followed them into a large semicircular room. There was no one else there and their footsteps echoed loudly on the tiled floor. At the far end was a strange metallic apparatus, four huge gleaming p.r.o.ngs of metal converging, a giant silver cross. X marks the spot.

Kerstin felt as if she were walking on air.

The Doctor and the woman walked up to a desk in front of a gla.s.s wall which part.i.tioned off the strange device, sitting down in swivel chairs before it.

Fitz was standing next to her, looking around in wonder. He caught her eye and grinned sadly. 'Well, this looks like the centre of things.'

'What is that?' asked Kerstin, pointing at the gleaming cross. 'Who is that woman?'

'Professor Jennifer Nagle,' said Fitz, scratching his chin. 'And as for that thing, I don't know. But the Doctor mentioned something about a wormhole, whatever that is.'

'Don't you know what a wormhole is?' said Kerstin, incredulous. Her knowledge of science wasn't great, but she read some of the popular science magazines. 'I thought you said you travelled in time!'

Fitz avoided her eye. 'Well, I am still rather new to all this.'

A wormhole was a tunnel through s.p.a.ce and time connecting two places. s.n.a.t.c.hing people from their beds and sending them to an alien world where they get infected with alien viruses and Kerstin felt herself slipping down again. Into the lake. Drowning. Everything out of control. A dizzying moment; how did she get here, with these people? Fitz, leaning against a desk, watching the Doctor and Professor Nagle, intent at a computer screen in front of the gla.s.s part.i.tion. This room, everything white. The walls, the chairs, the desks, all white. Clinical. Sterilised. It had the look and the smell of something secret and evil. The shining X at the far end of the room, the thing that had taken Johan from her. How long had it been here, underneath the forest? How many summers had she gone swimming in the lake with Johan, while the architects of his death lurked below? Had they meant to take Johan? Was this a weapon?

She walked up to the Doctor and Professor Nagle. Ignoring the woman, she addressed the Doctor. 'This thing killed Johan,' she said. 'You know that, don't you?'

The Doctor didn't look up, but he nodded.

'She's responsible for this,' she whispered.

Nagle looked up. 'It was an accident,' she said. 'I'm sorry if '

Kerstin lunged at Professor Nagle, pinning her against the desk, screaming, screaming, wordless rage pouring from her throat. She had her hands round Nagle's throat. The American woman wasn't very strong and Kerstin squeezed harder, wanting to kill her, wipe out her life as she had wiped out Johan's life.

And then she felt strong arms around her waist, dragging her backwards. She didn't let go of Nagle, who was making a funny gurgling sound and her face was turning red.

And then Kerstin felt a sharp pain at the back of her head, a flash of light and then darkness.

Captain Rogers stood over Kerstin's p.r.o.ne body, breathing heavily, his gun in his hand.

The Doctor's eyes were like chips of ice. 'You didn't have to do that,' said the Doctor. He then turned to tend Professor Nagle, who was gasping and rubbing her throat.

It had all happened so quickly, thought Fitz. One moment Kerstin had been chatting to the Doctor and Nagle, the next moment she'd dived forward, her face contorted in fury. He'd tried to drag her away. He hadn't heard Captain Rogers come into the room.

He bent down to Kerstin. She was out cold. Fortunately Rogers had only fetched her a glancing blow with the b.u.t.t of his pistol there was a small cut, a little blood. If he'd cracked her skull, caused a brain haemorrhage...

'She'll be all right,' said Rogers awkwardly.

Fitz glared up at him. 'If you'd had a clear aim you would have shot her, wouldn't you?'

Rogers coughed and reholstered his gun. 'She was attacking the professor.'

'I don't blame her,' said Fitz, fighting down his anger.

'I want that b.i.t.c.h arrested,' croaked Nagle, rubbing her throat. This was too much for Fitz. He shot to his feet, bunching his fists. 'You're responsible for the death of her boyfriend. And others. And Sam!' He was shouting. The Doctor was just sitting there, staring at Fitz.

Nagle stuck her chin out. 'As I said, it was an accident. I never meant for anyone to die.'

'An accident!' spat Fitz.

The Doctor stood up, put his hands on Fitz's shoulders. 'Fitz, Fitz, this isn't helping. There's a time to be angry and it's not now.'

Fitz ground his teeth. The Doctor was right. He was always b.l.o.o.d.y right. He remembered the last thing Sam had said to him. He's a hero and he never; never, never does anything wrong. He's a hero and he never; never, never does anything wrong. Well, he, Fitz, wasn't a hero. And he sometimes did the wrong thing. So what? 'All right, OK.' Well, he, Fitz, wasn't a hero. And he sometimes did the wrong thing. So what? 'All right, OK.'

The Doctor nodded, and whispered, 'I've got work to do. Make sure Kerstin's OK and keep your eye on Captain Rogers.'

The Doctor sat back down at the control desk next to Professor Nagle.

Rogers was standing nearby, eyes narrowed.

Fitz beckoned to him. 'Come on, help me get her into a chair.'

Between them Fitz and Captain Rogers carried Kerstin to a seat on the other side of the room. Her head was lolling against her chest and Fitz leaned her back against the wall, making sure she could breathe properly. Then he noticed that Rogers had slipped away, back to the Doctor and Nagle. Fitz followed, his eyes on the soldier's gun. d.a.m.n. He should have disarmed him when he had the chance.

'What exactly are you up to?' said Rogers. 'You know that we're evacuating.'

Nagle glanced up at him. 'Has everyone gone?'

Rogers shrugged. 'Not everyone. It's going to take time to dismantle everything. Lindgard's still here somewhere. As is the major, of course.'

Ah,' said the Doctor.

Nagle returned her attention to the keyboard.

Rogers frowned. 'You're not planning on switching that thing on, are you?'

'No,' said Nagle.

'Yes,' said the Doctor at the same time.

Captain Rogers went for his gun. It was the chance Fitz had been waiting for. As he reached inside his jacket, Fitz grabbed his arm and spun him around, pinning him back against a desk. The Doctor sprang up to help, and between them they disarmed Rogers.

The Doctor handed Fitz the gun, a look of distaste curling his lips.

Fitz pointed the gun at Rogers.

The soldier's eyes were wide. 'This is madness. You know what'll happen if you activate that thing?'

'No,' said the Doctor. 'But we can't leave it alone. Someone has to go through.'

Captain Rogers shook his head. 'Professor Nagle, you cannot allow this! This base is under military command.'

Fitz heard Nagle's hoa.r.s.e voice. 'So what. We're trying to save the planet.'

Fitz kept the gun steady, aiming at Captain Rogers's chest, at the middle b.u.t.ton, bright against the green fabric of his jacket. He kept his eyes locked on the soldier's. They were dark brown, with large pupils. Fitz hoped he looked menacing enough, hoped he looked like the sort of person who would shoot first and ask questions later.

But what Captain Rogers said and did next gave the lie to that.

'This is totally preposterous,' said Captain Rogers, his jaw firm, resolute. 'I'm going to get the major and you, sonny, are going to have to shoot me to stop me.'

With that he turned on his heel and marched stiffly out of the room.

Fitz stood, the gun useless in his hands. He just couldn't shoot somebody in cold blood. There had been Ed Hill, of course. But he had been just about to destroy the world. Rogers was just doing his job.

Still aiming the gun, he shouted to the Doctor. 'He's getting away! What shall I do?'

The Doctor's face was dreamy, abstracted, totally absorbed in the computer screen before him. 'Oh let him go, he doesn't matter. This is far more important.'

Chapter Fourteen.

Hating the Alien Sam had been swimming or flying for what seemed like ages, but there was no sign of Itharquell. There seemed to be no end to this golden sky-sea it was as if she moved through in an endless realm of golden light. She had no idea how much time had elapsed since she'd arrived in the Dominion she hadn't been wearing her watch when she was taken from the TARDIS but she felt hungry and light-headed. And tired again. Maybe this place was br.i.m.m.i.n.g with ambient radiation which was slowly but surely killing her. She remembered Ja.n.u.s Prime, with its strange glowing sands, and the radiation that had almost claimed her life. Well, at least that had been a planet. This place was... well, what was it exactly? A whole separate universe of rock, as Itharquell seemed to think? No, it had to be a planet, so vast that the inhabitants had never seen the surface.

Here and there floated clumps of rock, covered in rubbery tubelike growths, and she could mark her progress against these. She rested for a while, sitting on one of the lumps of rock, the surface of which was covered in a dense purple moss.

She glanced down, and screamed, leaping from the rock, hardly able to believe what she had just seen.

A face, a human face.

She moved around the thing she'd been sitting on. It had once been human. Its body was covered in purple growths, the only recognisable parts the face and left shoulder. Grimacing, she moved in for a closer look, praying it wasn't the Doctor or Fitz. But it was a youngish man, with blond hair.

How long had he been here? What was that purple stuff? She panicked, inspecting her skin. What if it started to grow on her?

She had to get out of here.

She kicked off from the rock, peering ahead. Nothing but an endless honey-golden glow, streaked with currents of white and amber.

Then, before her, she saw the gold of the sky-sea darkening to ochre. She knew that this was where it met a cavern. Perhaps that was where Itharquell had gone. She moved towards it. Now she felt as if the surface was above her, and she was rising up to meet it. She couldn't see clearly through there could be anything on the other side so she slowed her pace, until it got closer, closer, and then she popped her head above the surface.

As she did so, something buzzed past her face, wings flailing, and she put her hands up to protect herself, kicking her legs. The movement propelled her out of the sky-sea, spinning away into the cavern. Out of control, she spiralled down, her vision flashing gold, then blue, as the sky-sea and the cavern spun about her, the floor rushing up to meet her.

As she fell, she caught glimpses of furious activity on the far side of the cavern, and heard terrifying screeching and howling. The unmistakable clangour of battle.

Sam landed with a soft b.u.mp. She was in a cavern of powder-blue sand. Even the walls and roof were sand, held in place by the strange surface-tension gravity of the Dominion. Behind her, the golden sky-sea swirled like a vat of treacle for miles in either direction, meeting the roof of the cavern some hundreds of feet above her.

The ever-present flowery smell was even stronger here and it made Sam sneeze. On the other side of the valley, the ground rose up to a vast, black wall of rock, which was splintered like a broken mirror. At first Sam thought it was a patch of Blight, but it was still and shiny, reflecting the gold of the sky-sea opposite. It reared up hundreds of feet, a black shining cliff face. Before it were scattered angular shards of black rock, as if something had burst through from the other side and sent them scattering down the slope.

And, in the air above her, a battle raged.

There were at least a hundred Ruin, arranged in a ribbon formation in front of the black cliff, their orange bodies closed up into flower-like bulbs, propelling themselves across the cavern to lash out with their spider legs at hordes of winged green creatures. These occupied a flock of dirigibles near the ceiling of the cavern, from which they leapt and soared, pale wings carrying them into the fray, firing bolts from stubby harpoon-like weapons. Sam frowned. They looked like T'hiili, but they were somehow different. They had wings, to start with, and even from this distance they looked more substantial and st.u.r.dy than Itharquell.

Perhaps they were the warriors T'vorha that he had mentioned. The combatants were too far away to notice Sam, so she could watch in relative safety, work out what this battle was about.

It seemed that the T'vorha if that was what they were were trying to break through the cordon of Ruin to get to the black wall beyond. They weren't having much luck. The blue sand of the cavern was littered with their bodies, the wings crushed and folded beneath them. Some had landed on the shards of black gla.s.s, grotesquely impaled. A few tangled and deflated Ruin bodies lay here and there, but nowhere near as many as their opponents.

Something buzzed above Sam's head and she ducked down behind a dune, looking upward fearfully. She breathed out in relief when she saw that it wasn't a Ruin, but a strange, insectoid thing like an elongated dragonfly with a trumpet mouth and four wings. Now she came to look, there were quite a few of the things flitting about. This was the highest concentration of life forms she'd ever seen in the Dominion. What was so special about this cavern?

Sam felt, not for the first time, that she had more questions than answers.

Major Gareth Wolstencroft sat in his office behind his mahogany desk, looking at the wood-panelled walls, the photographs of his early days in UNIT. In the desert in Kebiria. In the Welsh valleys. Fighting monsters.

He wouldn't miss this place at all.

He hated being underground, and two years stationed in this base was more than enough for him. No place for a soldier. This place was perfect for C19 of course allowing them complete secrecy to carry out their experiments.

Well, that would all end now. There had been too many deaths. On the green leather of the desk in front of him was a full report indicting Professor Nagle of gross misconduct. It would go to UNIT headquarters in Geneva, and to the head of C19 in Whitehall. This pleased him: he'd never liked C19. The report would show them the dire consequences of mucking about with alien technology.

Wolstencroft believed pa.s.sionately in UNIT. They were a vital force. Earth had to be protected. It had always rankled that C19 were their paymasters. As far as he was concerned, any alien technology found or left over should be destroyed. Far too dangerous. His views were widely known, even at ministerial level. And the events here in Sweden would give force to them. He hadn't wanted to come to Sweden to start with. It had sounded a humdrum job: provide security for Professor Nagle and her team. But his superiors had made it quite clear: his views were not shared by others, and he was becoming a bit of an embarra.s.sment. So they'd farmed him out here. He smiled. They'd shot themselves in the foot there. He had enough evidence to force C19 into a severe audit.

One fly in the ointment. The Doctor.

Wolstencroft shuddered. The Doctor had been indirectly responsible for the deaths of his men on several occasions. Over the years, Wolstencroft had come to the conclusion that the Doctor wasn't on their side at all. He was an alien, after all, and Wolstencroft knew that you couldn't trust aliens. He may look human on the surface, but, beneath, Wolstencroft was sure that the Doctor had his own agenda. It seemed to include activating the generator, for G.o.d's sake. And that would only let more creatures through, cause more chaos.

There was a knock on the door.

'Enter,' he said, hiding the report on his desk under some other papers. Just in case it was Professor Nagle.

But it was Captain Rogers, and he looked unusually excited. He came up to the desk and saluted. 'Sir!'

Wolstencroft smiled at Rogers. Always so formal, yet always reliable. 'At ease, man. Now what is it?'

'It's the generator room, sir. I think you'd better come and see for yourself.'

The Doctor and Nagle sat side by side at the control desk. The screen was showing an intricate revolving pattern. Behind the gla.s.s part.i.tion, the silver p.r.o.ngs of the generator were starting to shimmer, like reflections in water. The Doctor and Nagle seemed unconcerned, even excited, but Fitz was getting a bad feeling about this. If the wormhole could invade the TARDIS there was no telling what it could do.

'It'll take a while to power up,' said Professor Nagle. She sighed. 'I don't think there's any hope of closing the wormhole. My generator's had it.'

'Oh, there's every hope,' said the Doctor. 'If I can shut the wormhole down, then the generator will function perfectly once more.'

'Great,' said Nagle.

'But I won't allow it,' said the Doctor.