'...inversion.'

James Rafferty relayed the last word of the message, removed the headphones and let them dangle incongruously around his neck. He raised his eyebrows at Ballantyne, Vaiq and Terrin.

'Strakk,' Terrin muttered. 'Clever boy. It might work...'

Ballantyne was horrified. 'A force-field? Against a molecular accelerator? We'd need '

'You'd need,' Terrin told him, looking him dead in the eye, 'all the energy this station can muster. Where are the deflector-fields usually regulated from?'

'Auxiliary control. But you '

'Tell me how to get there, Ballantyne. Now!'

The supervisor hesitated. Somehow, Terrin sensed that he was still reluctant to try anything unorthodox.

Vaiq seemed to uncurl into action, snatching an instrument-box from a nearby rack. 'I'll take you there, Terrin.'

'You were just a carrier,' said the Doctor, in answer to Tom's unspoken question.

The boy stood by Ace, watching as water and space twisted into a towering figure. Sparkling like a mirror, its surface reflecting crackles of Time-energy, the Garvond grew as it drew its final strength from the power of the TARDIS.

The Doctor spread his arms out behind him. It was a simple gesture, but one which Ace knew. He was ushering her and Tom back, to protect them.

'I think,' the Doctor murmured, 'that I may have made another slight miscalculation...'

'What do you mean?' Ace hissed.

'The Garvond is integrated with the TARDIS.'

Ace looked up, up as if at a sheer cliff. The sparkling Garvond stabbed at her eyes and she suddenly found she was meeting its hollow gaze.

It swooped.

Station Q4 was on red alert. The alarm echoed through its near-deserted walkways as Terrin and Vaiq ran, keeping pace with each other.

They leapt into the elevator, which took five seconds to convey them to the tiny auxiliary control centre of the station. Terrin saw an almost featureless room lined with slender consoles.

'You know where to look?' he asked, breathless.

She nodded curtly, tapping out a coded sequence on her wristband. A section of console pivoted, and the relevant hardware slid from its compartment into the room. Terrin saw a thick tube, bristling with circuit inlays and connectors.

'Field generator,' she said. 'We just have to persuade it to be a little ambitious.'

Terrin and Vaiq crouched opposite each other, one either side of the generator.

'If we don't get this rigged in time...' Henna Vaiq murmured, her dark eyes troubled, 'we could all be skinned and boned before we know it.'

Terrin shook his head, and grinned. 'I'm all right. I've been here next week, remember?'

Vaiq was making adjustments with a laseron probe, her face set with concentration. 'I reckon the Doctor would say that Time doesn't work like that.' She threw him another tool, which he caught instinctively. 'Patch in reinforcers to all all the ectopic condensors on that side. And do it the ectopic condensors on that side. And do it fast fast.'

Terrin gave her a a mock salute, and set to work with grim resignation.

The Garvond, looming in fire etched upon the water, directed its mental force. But Ace, steeling herself for the impact of blackness she had felt earlier in the engine rooms of the Icarus Icarus, sensed nothing.

Beside her, the Doctor cried out and fell to the cloister floor, clutching his temples.

He was in an open space, framed by concrete. Echoes bounced around him in the darkness. There was a noise, he made it out now, of dozens of revving engines, and a smell of fossil fuels. He stepped out, cautiously, feeling concrete beneath his toes, and the CityLink bus hurtled past him, thick-wheeled, dark-windowed. Heading out into oblivion.

The Doctor's hearts were pounding. He could see the Garvond, cowled and waiting like Death in Bay C of the bus station. So it was playing with him now. Playing off his deepest fears... Gritting his teeth, he strode out across the bus station concourse. He tried to ignore the lost luggage that swarmed like yapping dogs around his feet.

A table stood before the grinning skull of the Garvond. The Doctor, his face ashen, looked down.

The chessboard was of the highest quality pine and mahogany, beautifully varnished. Just a few pieces remained on the board, enough for the Doctor to recognize the paradigm, filched from his memory.

'Byrne and Fischer,' he whispered. 'Black playing the Gruenfeld defence.'

Just one game, Doctor. Always, it comes down to one set of moves, among so many. When you would explore, and play again and again...? Yes, I sense it now!

The Doctor gathered all of his weakening telepathic resources. But nothing, it seemed, could block out the Garvond.

Yes... not losing, no, that is not it. Rather the game left abandoned, of the enigma unsolved. The unexplored knowledge of the universe! There was a lilt of fascination in the Garvond's voice, an intrigued purr creeping into its inhumanity. There was a lilt of fascination in the Garvond's voice, an intrigued purr creeping into its inhumanity. Yes, Doctor. THAT IS YOUR GREATEST FEAR! Yes, Doctor. THAT IS YOUR GREATEST FEAR!

The Doctor was silent.

Around him, the bus station had shimmered into a dark void once more. And towards him came another, familiar figure.

Ace had fought the tugging of her memories as long as she could. But now, the insistence of it overwhelmed her. She was no longer in the TARDIS cloisters with Tom Cheynor, shivering below a creature none of them seemed to know how to fight.

She was facing the Doctor.

He stood, pale, in a cone of blue light, his hands gripping the rail of the courtroom dock. And her own hands were tight around the butt of her gun.

Alight with unearthly power, the Icarus Icarus solidified fully, thundering on into the void. solidified fully, thundering on into the void.

On the bridge, the leading Time Soldier's fist clenched in triumph.

Our Lord Garvond has made contact!

The Time Soldier at the weaponry console seemed to shimmer with power, his hands uniting with the surface of the control panels.

Strakk exchanged a desperate glance with Bernice. She raised her eyebrows, as if coolly inviting him to do something.

You know he is guilty. You know he will betray you again.

The voice was lulling Ace, echoing in her mind like seagulls off a shore. She saw the faces of those she had known and loved, those who had died, and behind them, the agonized eyes of the scarred survivors. She saw death tearing through a world she had known as true and real, not too long ago.

She sensed the tears welling in her eyes. Meeting the Doctor's impassive gaze, she drew the pistol up.

The Garvond's voice became like a lead hammer, thudding into her brain. Riveting one single thought.

She fired, point-blank.

Around her, the water of the cloisters sprayed furiously onto marble, as the gun shattered into a million pieces.

Strakk's foot was curling, taking the strain. Bernice saw him. Her eyes said No. Alarmed, she looked at Cheynor for support. He was staring into space, distant, defeated.

Benny felt tragedy hurtling towards her in tangible waves.

When Strakk launched himself forward, she called his name, once, sharply, in anger.

He smashed into the weaponry operator's shoulder, and was hurled off in a blaze of sparks. He hit the deck at Benny's feet, just as the whole ship tilted, throwing the group of humans off-balance.

The engines were screaming now, blotting out all other sounds. All but one. The voice they had come to fear echoed round the bridge.

Target in range. Prepare for Time acceleration.

Vaiq's communicator hissed into life.

'Vaiq! Are you ready? They're right on top of us! Now, Vaiq, d'you hear me?'

'I hear you, Supervisor.' She snapped her panel shut. 'Just the final link.'

Terrin looked up. 'Right. So get out.'

Vaiq's face was hard with anger. 'We haven't locked into the main generator!'

'I know,' said Terrin. It looked, and sounded, as if this was something he had been planning for longer than Helina Vaiq could have known. 'When we lock in, there's bound to be massive molecular feedback. It's going to kick through every circuit in this room, and there's going to be one hell of a burn-up. The equipment wasn't designed for this kind of strain!'

She clicked her tool-kit shut. 'So we'd better not be in here.'

'Someone has to make that connection!'

'It would take two minutes at most to set up a simple remote '

'We haven't got two minutes.'

'Terrin '

'Get out of here!' he yelled.

For one brief, fragile moment, she saw the intensity in his eyes, and knew there was no use fighting it.

'Promise me you'll get out,' she said softly. 'If the relays give you time.'

He didn't look up.

Vaiq took a deep breath and slammed the elevator-control.

The hydraulic seal echoed with a snap of air, and she ducked out, her heartbeats shaking through her.

As the lift sped back to the upper levels, she swallowed hard. The fire was raging in her mind again, the intense, napalm-burn image, bringing burning tears to her eyes.

Somebody might have learnt how to fish today, Doctor, she said to herself.

'Come on, Ace!'

It was Tom Cheynor, pulling her roughly from behind, the water cascading all around them. Above, the Garvond was like a storm-cloud, etched in its own incandescent lightning, drawing its final surge of power.

'No!' she yelled. 'The Doctor!'

He was crouched on the soaking cloister stone, dwarfed by the time-creature.

The illusion had vanished around Ace when the gun shattered, and now she had realized what she had to do. It had come to her, in that split second when she'd realized she really was capable of pulling the trigger. She truly thought she'd done it.

So now, she just had to get him out of here.

Terrin could see the two zirconium connectors. All he had to do was slide one along the tube with each hand till they hit. Kissing with power in the centre. And there was no way of damping the feedback surge. Not now.

The communicator voice was yelling angrily at him, its sharpness driving into his mind.

He remembered Josh Kenley, his old friend, reduced to such a voice. His screams, filtered through the vacuum from that ghost settlement on Rho Magnus where he'd died. Coming out of the com-link grille, in the shuttle where Terrin had just hit escape velocity.

Screaming at him not to leave.

Only Kenley didn't know had never known that if he'd been taken back, then the berax spores that had infected his body would have killed the whole crew.

And Terrin would forever have been responsible for the deaths of two hundred. Instead of one.