Ace stood under the ladder-shaft, listening.

'It's happening,' she said quietly. 'Whatever it was has caught up with us.'

Dr Mostrell, who was trying to link up the auxiliary power, had a mess of optic-fibres in his arms. 'If I can get this back,' he said, poking around in the electronic spaghetti with a laser-probe, 'we can see what's happening on the bridge.'

The sound of the catch on Strakk's Derenna-24 cut the air like a knife into ice. 'If they get down here... we'll be ready.'

'Don't count on it, boy wonder,' Ace snapped. 'It kicks Time around the way kids splash in puddles. If they haven't killed us yet, it just means the bastards haven't got round to it.'

Strakk's dose of benzodiazepine was wearing off. 'Are you always such a ray of sunshine?'

The thunder of battle roared again like a tidal wave. And this time, it sounded closer than ever.

It had begun in Hold Five, with flickers like ignis fatuus ignis fatuus in the darkness, and then the globules had resolved themselves into larger shapes. The walls were no obstacle. Forming details limbs, helmets, broad-nosed blasters as they entered the real world, the Time Soldiers leapt, de-phasing, through solid metal. Traces flickered behind them like after-images. in the darkness, and then the globules had resolved themselves into larger shapes. The walls were no obstacle. Forming details limbs, helmets, broad-nosed blasters as they entered the real world, the Time Soldiers leapt, de-phasing, through solid metal. Traces flickered behind them like after-images.

In the dimness of the access tunnel, the echo of advancing feet was distant, yet growing louder.

Tristan Cobain wiped away a trickle of sweat from his nose and glanced along the barricade at his security team. In the red lighting, their faces were drained of emotion. It was the only way, Cobain thought grimly. In his five years as security chief, he'd seen it every time. You had to think of each man and woman as fighting units as components. They were human beings Cobain never allowed himself to forget that, and he knew Captain Terrin wouldn't either if he were still here but you had to forget their human failings. You had to have your team, and orders needed to come from the head, not the gut. Cobain had never believed in instinct. He'd seen three good mates die from relying on it. He looked at the faces once more. No one's eyes could be seen behind their goggles, but he knew they'd all be watching the door to the hold. They were more than just gun-arms. He knew them, although he got little chance to show it. Katja Brintz, nineteen last birthday and two months pregnant. Brad Gillespie family killed in the Cyberwars. Drew McCarran, whose sister was a TechnOp on the bridge. There were others. They were never just 'you'. They had faces, names, hearts that thumped, families on the Colonies. They had lives and loves and hates.

Cobain did too. He especially hated the silence.

So as he listened to the clangs and shudders from deep behind the metal, he was not wishing them away. He wanted the sound to grow, until it was tangible. He wanted them there.

Tristan Cobain needed to see what he was killing.

The steel shutters burst outwards in a fountain of light-globules.

'Open fire!'

Cobain's order snapped the tension. The air was shredded with blue light.

The invaders, their bodies taking form, did not even attempt to get out of the way. The lasers sliced through them, diffusing as if pushed back by invisible hands. In slow motion, with a fluttering and twittering, the Time Soldiers raised their right arms. Time shrivelled in beams between the blasters and the squad.

Three bodies were hurled against the wall. Two were skeletons, and the third a mass of torn flesh, the bone of his tibia and fibula crumbling beneath him. Cobain was showered with powdered skin and bone. That was Gillespie.

The screams of death were taken up from somewhere behind the creatures' masks, as if in mockery, a banshee parody of the troopers' agony. A cry of battle, feeding off a cry of death.

Cobain fired bolt after bolt. On the invaders came. He yelled at the squad to fall back. It was all they could do. At the portal, Cobain's fist slammed the sealing control. The force wall shimmered down between the aliens and the remainder of his squad.

All but one, Katja Brintz. She had tripped, fallen.

He could do nothing but watch in horror as the invader, floating two metres above her, fired straight into her stomach.

The force-field was splitting open. The invaders poured through like water smashing a dam.

It didn't happen quite quickly enough for Cobain to miss what had happened to Brintz.

The beam had slammed her up against the wall, her skin bleaching. But there was something else emerging from the point of impact. Something with a face, and tiny glistening hands.

Cobain's eyes widened. There was an invader stabilizing just in front of him, and he tasted the coldness in the air now, but he was rooted to the spot by Brintz's screams.

No. They were not her own.

They were the screams of something coming to life, being born into terror, pumped full of accelerated life as it lifted itself... towards death.

In the aura of energy, Katja Brintz's hair crisped and shrivelled to death-white. And in the shattered remnants of her womb It was the last thing Cobain saw. His head, wrenched from his body by a beam of Time, hit the bulkhead. His skeleton split and fractured in the rays, cracked like fine china.

And on the Time Soldiers came.

They knew there was no need to hurry.

Cheynor slammed the headphones down. 'Recall the guards,' he snapped. 'I've heard enough.' He rounded on Larsen. 'Can we patch in extra power to defences, without losing full life-support capacity?'

'I can try, sir.'

'Good.' Cheynor was gnawing at his finger. He shuffled the events like index cards in his head, ready now to look up the next thing to do.

Quallem, in Strakk's vacated chair, was recovering from the minimal stun-bolt. Cheynor lifted her chin, gently.

'Lieutenant-Commander, can you hear me?'

Her eyes were like polished stone on crumpled cushions. 'I feel like shit,' she said.

'Good. Means I didn't hurt you too much.'

Her voice was gentle, nothing like the metallic tones which Cheynor was used to. 'I can hear the birds. In the morning, over Lac Durenne. Flying against the sun.' She looked into Cheynor's puzzled face. 'Rooks. Their voices are black, ebony-black. And Maman is holding my hand.'

'Quallem...' he murmured, and realized that the woman could not hear him. He cast a desperate look at the TechnOps, who were trying their best with their various tasks on the rapidly draining power. The monitorscreen was blank as well, now, and all communications channels seemed to be filled with the sound of the demonic flapping of wings.

He turned back to her, touched her cheek gently. Her skin was burning.

'Listrelle... I'm so sorry...'

Her mouth was damp. A smear of lipstick ran from its corner up to her temple, like a bloodstain. Her eyes suddenly cleared, fixed on Cheynor properly, and she gave him a delighted smile.

'Les oiseaux du temps,' she said. 'Je les entends. Ils viennent.'

The birds of Time.

Darius Cheynor was suddenly, inexplicably sad that he had no children.

Chapter 11.

The Riders 'The helmsman steered, the ship moved on; Yet never a breeze up blew; The mariners all 'gan work the ropes, Where they were wont to do; They raised their limbs like lifeless tools We were a ghastly crew.'(Samuel Taylor Coleridge, The Rime of the Ancient Mariner)

'Time, Co-ordinator. It's all a matter of Time.'

Helina Vaiq leaned back in the leather chair of her office and looked at the strange man across several square metres of mahogany.

'Doctor,' she said, 'the Earth colonies currently have no major enemies. We're enjoying the longest period of interplanetary peace since the Cyberwars. Even if I were to believe that this weapon existed, who is there that would want to use it against us?'

'I assure you, if my theory is correct, then the period of peace is rapidly coming to an end,' the Doctor murmured.

Helina slipped out of her chair and went to stand at the viewing gallery that bordered one side of her carpeted office. She fixed her gaze on the whirl of stars, and remembered the hologram museum on Earth where she had first seen it.

'If we ignore you and you're right, Doctor, we are going to look utter fools. On the other hand, if we take you seriously and you are a crank, we will also look utter fools.'

'Then maybe you shouldn't decide,' suggested the Doctor, and he felt his two hearts beating with renewed energy. 'Maybe you should wager.'

The woman's eyes opened wide and brilliant white against her ebony skin. 'Wager?'

'You weigh up the potential losses and gains. There are four outcomes. You ignore me, and I'm right or I'm wrong. You take my advice, and I'm right or I'm wrong. Which scenario gives you the least chance of losing, Co-ordinator? Which would you rather be reviled as a gullible fool, or reviled as a gullible fool and very much dead into the bargain?' The Doctor took out his paisley handkerchief and mopped his brow. 'Are you familiar with the work of Blaise Pascal?' he added.

Vaiq looked surprised. 'I've studied his logic.'

'Charming man.' The Doctor broke off, looked into the distance with slight regret. 'I wonder if he remembers me?' He realized that he had better not pursue that particular line of thought. 'So if you arrange to believe me what have you got to lose?'

Helina Vaiq sat down, and rested her chin on her hand. Then, as if coming to a sudden decision, she pressed a button on her computer keyboard and the lighting in the office gave a slight flicker.

Almost in anger, she spun the VDU around to face the Doctor.

'My computer says you're telling the truth, Doctor.'

'I suppose I should take that as a compliment. Do you humans ever think for yourselves yourselves?'

'Yes, Doctor!'

Even the Doctor was surprised by the vehemence of Vaiq's response. 'Go on,' he said.

'I was born on the Abema colony, Doctor. Thirty-three years ago. We lived under plastic, corrugated iron, anything we could salvage. The plastic came from crashed shuttles. For some reason there were lots of them. So we had plastic huts on mud floors. We had a vidscreen, can you believe it? There was a central relay and everyone had their set tuned into it. Hundreds of sat-channels, and yet our sanitation was a hole in the ground. There were meant to be food drops every week, but sometimes they didn't get through. So when someone died, the family did what was best for the community.' She paused, her face hard with memory. 'You get used to the taste of human flesh, after a while. It's still like that on some of the colonies. You tend to grow up pretty fast in that kind of place. You do think for yourself.'

The Doctor had pressed his fingertips together, and was listening. Someone he didn't remember who had told him once that he never liked to listen enough.

'The tanks came in when I was eleven. Our settlement was fire-bombed. They took the survivors. I don't dwell on how I got by, Doctor. If it hadn't been for a major who needed an unquestioning, uneducated secretary, I'd have been roasted on a spit. Or forced to perform unspeakable acts on members of my family, like some of my friends. As it was, he let me go in a couple of years, gave me enough money to get a Corps education. I was the lucky one. So when people call me an unquestioning follower of technology and orders, I don't tend to disabuse them.' She sat back, a little embarrassed by her outburst. 'They feel chastened afterwards.' Helina slammed her fist down on the desk. 'Why am I telling you this? You, a prisoner. Maybe there's something about you makes me think you'd understand that kind of thing.'

'Nothing can equal the cruelty that humans inflict on one another,' said the Doctor softly.

'So,' she shrugged, tapped her fingers on the arm of her chair, 'maybe that's why I believe you. Maybe I think you've suffered too, in the past, and that's why you understand it. Am I right?'

'Maybe.'

'All right, Doctor. So what the hell am I supposed to tell Ballantyne?'

'Somehow, the captain and I have been transported back in time one week. I'm not clear why, or how. Normally...' The Doctor sighed, remembering. 'Normally I could not interfere to save those who I know will die. But the true path of Time has been disrupted.'

'But how '

'Don't ask. It's something people like me feel, like the mugginess before a thunderstorm.' He got up, began to pace up and down the office. 'If only I didn't feel so trapped... and there's something nagging at me. I've felt it ever since I left Oxford...'

'Which was when?' Vaiq asked, casting caution to the winds. She did not expect to get a logical answer.

'Yesterday. Time flies. It seems like only four hundred years. Co-ordinator Vaiq what exactly goes on here on Station Q4?'

She shrugged. 'What the hell. If you're a terrorist, you know enough for me to be court-martialled anyway. We're right at the edge of this spiral arm. We're the marker buoy in one heck of a big sea. We've got probes out there at the moment, to tell us what they've found, and so far, it's the usual stuff. Magnetic fields, asteroid belts. Q4 is one edge of Earth's colonial civilization, Doctor.'

'And so anyone attacking this station,' said the Doctor thoughtfully, 'would know exactly what they were doing...' He was whispering now, almost to himself. 'A memory, a suspicion... it annoys me. Like picking through the rubbish in a dimensionally transcendental filing cabinet. Must get it sorted, one of these days.' He looked up at Vaiq again, as if remembering she was there. 'Reminds me. If you should come across a blue box, about two metres high, would you let me know? Unlikely, but it might just turn up. The way these things do.'

'Anything else?' Vaiq was incredulous that she took this man seriously. And yet, she thought, she had to right? The wager. A fool or a dead fool, take your pick. She had to let him know where she stood, though. 'Doctor, I'm afraid Ballantyne runs this station, not me. And until he has proof he'll do sweet nothing.'

The Doctor leaned on Vaiq's desk and looked into her striking brown eyes. His face, she noticed, wore its first hint of fear.

'The proof,' said the Doctor, 'might be too terrifying to give.'

Romulus Terrin paced the cell for the hundredth time, his patience in a decaying orbit.

His mind kept slipping away from the anonymous greyness of the cell, back through time. Back to the staring skeletons of the dead Q4.

What kind of creature could leave a whole space-station a husk like that? Like a grape being squeezed of its juice, he thought, dried to a raisin, but worse than a raisin beyond, to a shrivelled, stumpy blackness.

Terrain had seen death before. Once or twice, he had been too close to it. He wondered, again, what Kenley would have made of it all. Joshua Kenley, his old first officer and friend, might even have been able to get a way out of this blasted cell.

But there had been one thing that even Kenley, the infinitely adept, had not been able to talk his way out of. Berax spores travelled faster than any other bacterial organism, Terrin had known that. He'd also thought the Rho Magnus settlement had been totally sterilized before they got there, but that was a pretty misplaced assumption. It only needed the smallest of cracks in the sterilizing foam and the berax spores, if they were resourceful enough, could pour through it. As they had done. And one thing that berax spores always needed, especially after months of forced, frustrated incubation, was food.

Reinforced plexiglass and gold anti-glare film had been the first food of this particular batch. They wouldn't have liked that, Terrin remembered thinking at the time. When they got through to Josh Kenley's eyes and brains, those would have been more palatable.

That had not been the terrible thing. The terrible thing had been what came after.

Terrin shuddered briefly. He shut it out of his mind, as he could now.

And Kenley would have been a lot more adept at understanding what the Doctor was about as well. Strange chap, the Doctor. He'd accepted all of this time-displacement business as if it was something he did every day.