'Utterly typical,' beamed the Doctor, encompassing the whole room with a grandiloquent gesture. 'She latched on to the first available technical expert in an attempt to survive. Putting number one first.You were a convenience, Nivet. Though I'm very grateful.' He started to manipulate the controls. 'Sadly, there's no sign of current activity in her identity circuitry, so she must be recuperating and regenerating her conscious persona. Have you been able to do anything with the telepathic circuits, Nivet?'

'First thing I thought of,' admitted Nivet. 'This vessel has a kind of mental link to the Edifice.

It's very recursive, though, like ...'

'Yes?' prompted the Doctor. 'Like ...'

'Well, the same effect you'd get if no surely not.'

The Doctor smiled at Nivet, encouraging his bright pupil.

'Well, the same effect you get when two TARDISes are interlocked. You're telling me that the Edifice is a TARDIS?'

'My TARDIS,' said the Doctor, like a proud parent at a baby show.

Nivet looked astonished. 'But there are trace elements of thousands of different planets embedded in the external structure, and in millions of different times.'

'Well, I've travelled widely,' muttered the Doctor. 'Not all Time Lords are unimaginative unadventurous stayathome dullards, y'know.'

'Thanks,' said Nivet.

'Now,' continued the Doctor briskly, 'let's see about those telepathic circuits ...' He placed his palms flat on the console and closed his eyes. 'Ah yes, some evidence of a connection to the Edifice, and Aagh!'

Suddenly he was no longer in the TARDIS. He was swirling in an eddying vortex of visions and sounds and scents, some powerfully familiar, and some that resonated on the edge of his mind. He was frightened and delighted and nostalgic and regretful. He was spinning through some past that he had never experienced, but had always known.

In the centre of his mind a sharply defined crystal poured its calm blue light in a cleansing flow through his synapses. There were halffamiliar creatures here huge spiders not the bone monstrosities from the Edifice, but larger, hairier, more threatening, more fearful creatures from his past.

His past?

He was in a blue cave, and the spider queen leered down at him. She didn't need to devour him, though she could have crushed him with the slightest movement. Or with the slightest thought. She knew he was dying already.

He fled the cave and struggled to the TARDIS.

The door slammed behind him, and he fell against the console as a random dematerialisation began, taking ... taking him ... taking him to ...?

He sat up abruptly. He was in a crumpled heap on the TARDIS floor, in a patch of scattered glass and pottery fragments. He wondered where his darkblue jacket had gone, and then he saw he was wearing his familiar dullgreen velvet frock coat.

Why was that woman standing over him like that?

It was Combat Elite Mali. She had taken the opportunity offered to her by his sudden telepathic attack. She held a knife to his throat.

'Don't move,' said Mali coldly. 'Now that we have the Type 102, we no longer need you, Doctor. We will return to Gallifrey at once.'

'You don't understand,' mumbled the Doctor. 'I know what's happening here.'

'I understand perfectly; snapped Mali, and pushed the knife closer. "The virus has taken hold of you, Doctor. You're a Faction agent. You are the enemy. Resist me, and I'll kill you right here.'

Chapter Twenty-six.

Discontinuity

The Doctor stared at Mali, affronted. 'You stupid young woman!' he yelled. 'You're completely missing the point! I'm not a Faction agent.'

Mali stared down at him, unmoved. 'Your biodata is riddled with their virus.'

'No!' The Doctor shook his head, and felt the knife scrape under his chin. 'It only probably is.'

'Doctor, you're not making sense.'

'Listen. Listen to me very carefully, because I've just worked this out and the logistics are giving me a headache. I don't want to have to repeat myself: He pondered for a moment, looking rapidly between Mali and Nivet. 'Perhaps I should write it down. Anyone who gets lost could flick back a page and catch up.'

Nivet sighed impatiently. 'Well, Doctor?'

'Just then, while you were laying your hands on that knife, I wasn't having a seizure, I was connected to the TARDIS telepathic circuits. The circuits in my TARDIS, out there in the Edifice. I was able to push through the shadows and commune with her.'

'Shadows?'

'Shadows and cobwebs, yes!' The Doctor sniffed. 'Do you know,I don't think she even recognised me.'

'The telepathic circuits must be worn to dust by now.'

'No,' the Doctor snapped. 'Not to Dust. To Metebelis III. Giant spiders. Eightlegs, Great Ones, blue crystals! I died on Metebelis, not on Dust.' Mali and Nivet were staring at him.

'Don't you see? The Faction altered my timeline, killed me before my time, thought they'd poisoned my body along with my history.' His eyes were gleaming. 'But when I finally did regenerate, inside the console room, the TARDIS knew it was wrong. She'd already reached out and communed with me, while I was locked up and at my lowest ebb. She helped me then, put me in touch with my former self she must have known my future history. And she sensed that the Faction had changed things.'

Nivet was beginning to look excited. 'I've never known of such a bond between TARDIS and owner. An empathic interface of this magnitude is unheard of.'

'We've been through a lot together,' the Doctor said, shiftily, as if worried some impropriety was being implied. 'She's always helped with my regenerations. This time, she took the infected shadow of my dying incarnation into her own workings, holding it in temporal orbit.

When my next incarnation appeared, his shadow was his own, untainted.'

'And in doing so, the TARDIS negated the effects of the alternate timeline,' Mali ventured dubiously.

'Or deflected them, anyway. Undoing them. Abandoning the edited version of my life, and leaving it the way it was.'

Nivet said, 'Causality doesn't work that way.'

'It's not meant to, at least as far as we understand it. Maybe the old girl cribbed from a higher power. We have encountered one or two in our travels.' The Doctor smiled briefly.

Mali cautiously withdrew her knife, allowing the Doctor to rise.

'Thank you,' the Doctor said. 'I'm glad I'm explaining this to Time Lords. I think Fitz's brain would burst: Nivet rubbed his own head. 'But the energy required for your TARDIS to contain the potentiality of your diseased timeline would be vast, surely.'

'Agreed.'

'And it would increase exponentially the further on you travelled from the nexus point.'

'She tried to warn me the time was coming. She even took away my shadow. She knew she was facing her own death, and when the dimensional rift over Avalon finally tore her apart, she still held on!'

'How?' Mali wanted to know. 'What could've sustained your ship for all that time?'

'I'm not sure,' the Doctor confessed. 'But somehow she must have contained things. Perhaps because if she didn't, the events of Dust, the Faction's manufactured past, would've established themselves for ever.' The Doctor smiled sadly. 'She's a good, brave ship.'

Mali shivered. 'Not any more.'

The Doctor frowned. 'The spirit of my former self must've permeated the TARDIS over the millennia the Faction data inscribed in his cells gradually metamorphosing into the Edifice, like a cancer sweeping through it. The effort of will required to hold on to that strand of causality -'

'But you are infected,' Mali insisted. 'It's all been for nothing.'

'No. Not yet. The Edifice is holding two realities in place, or trying to. That's causing a buildup of temporal energy that could wipe out half the galaxy.'

Nivet shuddered. "The chain reaction could do a lot more than that.'

'But now -' The Doctor's eyes were bright.'! was never meant to arrive on Dust. I knew it at the time, it felt ... wrong. The TARDIS knew too her walls dripped with blood!' He slapped a fist into his palm. 'That's the trigger point. That's when things started to go wrong.

And that's the time we must return to.'

Mali looked appalled, and raised the knife again. 'If that isn't the voice of Faction Paradox, I don't know what is ... Doctoring your own past?'

'My probable past. Don't let all your degrees in temporal engineering cloud your judgement, Mali. Try to think like an indolent postgrad student who scraped a pass because he was fiddling about with experiments, not losing himself in theory.' The Doctor paced the floor. 'If we can only ensure that the right version of events is restored and confine my time on Dust to the wastebasket as an interesting experiment that failed.

'There will only ever have been one reality,' Nivet concluded.

'Precisely. The paradox will be resolved.'

Mali was sceptical. "The Edifice will remain a paradox itself.'

'Its energies will dissipate,' the Doctor insisted.

'But Doctor, don't you see?' Nivet seemed aggrieved. 'The reason the Edifice is so unstable is that the Paradox infection has spread right along its timeline, from construction to conclusion.'

The Doctor's jaw dropped. 'You're sure?'

Nivet nodded. "That thing's been bending causality round its little finger bone. To be inflicting the damage we've been registering it must be doing so throughout its lifespan.'

'But now we understand it, we can deal with it, yes? Score a real victory over the Faction.'

The Doctor held out his hand as if expecting Nivet to shake on it. 'Stabilise the core, trace back to Dust and undo the damage.'

Nivet looked doubtful. 'Assuming that's even possible, two things could happen. The Edifice may just blink out of existence, and you along with it,' he warned.

The Doctor shook his head breezily. 'Oh, I'll go on. If we do it right, I may never have been away.'

'What's the other possibility?' Mali asked, though she suspected she didn't want to know the answer.

'We're looking at a ship on the point of collapse,' Nivet said. "The tiniest tweak on any of those ossified controls, the whole thing could blow apart and take all of causality with it.'

'Which is precisely what the High Council are most worried about.' The Doctor looked across the debrisstrewn console at Mali. 'Do you still want to slit my throat, Combat Elite Mali? For the first time the Time Lords have the chance to seriously set back the Faction and their meddling! The Faction have slipped up at last thanks to the TARDIS's loyalty in trying to hold back time, I'm not their agent. I can fool them, gain their trust, correct my regeneration so that it no longer happens on Dust, then defeat them.' He smiled encouragingly at Mali. 'Call it a blow for normality.'

Mali brandished the large, dangerous knife and moved closer.

'I'm not a Faction agent!' insisted the Doctor. "They cannot know that this Edifice is my TARDIS. All right, I admit that they sent me here to discover its purpose and, if I could, to seize control so the Faction could use it as some kind of weapon. But now ...'

Mali stared at him for a whole minute. Then she said, 'I think it would be easier just to kill you now.'

The knife moved. The Doctor swung around the console to avoid it.

'I will not allow you to do that,' said Compassion's voice.

Mali and the Doctor stared at Nivet. 'It wasn't my fault,' he protested, eyeing the knife.

'Obviously,' sighed Compassion. Her face appeared, huge and menacing, on the scanner over their heads. 'Leave the driving to me, if you'd be so kind. You're making a right mess of it.'

At which point, the Doctor felt himself thrown across the console room and towards the battered exit doors. There was a brief, disorientating transition through the dimensions as Compassion ejected him from herself, and he was suddenly sprawled on the floor of the Edifice, brushing up against the chitlnous edge of a huge bone spider leg.

The spider scuttled away from him, alarmed. The Doctor glanced across at Compassion's battered exoshell. She was getting to her feet, the savage line in her midriff sealing as she did so and trapping Nivet and Mali inside her.

Compassion's eyes sparkled. The Doctor beamed back at her. She was alive.

He got up and hurried over to the console. 'Are you OK?'

She closed her eyes and considered the matter. 'I still feel the debilitating effects of being so close inside another TARDIS. Particularly this one.'

'Hardly surprising,' said the Doctor. 'My TARDIS was largely responsible for your becoming a TARDIS yourself.'

'You must take your opportunity, Doctor,' persisted Compassion. 'Escape the Faction. Start that regeneration on Metebelis, not on Dust, or you'll be doomed for all time.'

'And the Time Lords with me,' said the Doctor quietly.

Compassion stretched her limbs experimentally. 'I must make my own way, Doctor.'

'You can't leave!' shouted the Doctor, louder than he'd meant to. 'It's your responsibility to stay ...' As though disturbed by his anger, the spiders behind him cluttered nervously.

'Would you control me like the Time Lords?' Compassion cocked her head at him. 'Are you so different from them?'

The Doctor lowered his head, and slammed his hands against the wrecked console, so hard that his palms stung. 'I'm not like them.'

'Who would you save instead of them?' Compassion asked. 'Me? Fitz? Any individual? Any other race?' When he looked up at her, her swirling grey eyes bored deep into his. 'All other races?'

The Doctor was about to chide Compassion for her rudeness when he realised his palms were stuck to the console surface. The room was starting to fade away. He knew immediately what was happening. 'Stop this, Compassion.'