A grimace crossed Qixotl's face. The Doctor could hear Homunculette hyperventilating even from this distance. Justine shot a glance at Manjuele. 'Surely, some misunderstanding...'

'I told you,' Homunculette snarled. 'I told you not to trust them.'

The Doctor suddenly saw the way the Time Lord was standing. His muscles were tensed. His eyes were fixed on Justine.

'Homunculette, you promised ' the Doctor began.

But it was too late, of course. Homunculette launched himself at Justine, leaping over the table at the Cousin's neck. Justine was ready for the attack. She raised her hands, and grasped Homunculette's wrists, throwing him to the ground by the side of the table. Homunculette managed to drag her down with him, though. Manjuele leapt forward, fists clenched.

It was the spark that lit the flame. Suddenly, everybody's grudges against everybody else seemed vindicated.

E-Kobalt lurched forward, towards the Doctor. Presumably, the Kroton didn't realise the damping fields were off, so it was attacking with brute force instead of using its built-in weaponry. The table shattered as E-Kobalt ploughed through it. Gla.s.s fragments exploded across the room. The Doctor covered his face with his sleeve.

Nearby, Manjuele started kicking at Homunculette's head, but his blows were connecting with his Cousin as much as they were with the Time Lord. Colonel Kortez threw himself into the fray, whatever peace-keeping instincts he still had in his head obviously telling him to get involved somewhere. The Doctor fell back as E-Kobalt advanced, but b.u.mped into Mr Qixotl, and tripped over. Backwards.

E-Kobalt toppled sideways, knocked off its feet by Trask. The dead man was beating his fists against the creature's crystalline sh.e.l.l, his knuckles popping open with every blow. The Doctor had no idea why Trask was attacking the Kroton, but he was screaming something like 'he's mine, he's mine.'

The Doctor rolled onto his front. He was lying on top of Qixotl, and Qixotl looked terrified.

'Get me out of here!' Qixotl howled. 'Whatever you want, I'll do it! Just get me out!'

And there was something in that expression of utter horror the Doctor recognised. Something he'd seen on another face, a long time ago.

Finally, all the pieces slipped into place.

'It's you you,' the Doctor said.

Qixotl's face twisted itself into a mask of pure agony. 'I'm sorry! I'm sorry!'

'It's you,' the Doctor repeated. He grabbed the little man's collar, and felt the fabric rip as he hauled Qixotl to his feet.

'I said I'm sorry! What more do you want?' Qixotl tried to struggle free, but the Doctor kept hold of his lapels.

'Sorry?' the Doctor shouted. 'Is that all you can say? The last time I met you, you tried to sell me off to the Antiridean organ-eaters. Piecemeal! And two regenerations before that, you tried to turn me over to an Embodiment of Pure and Irredeemable Evil. I trusted you, and you betrayed me. It's you. I can't believe I didn't recognise you before.'

Qixotl kept struggling. 'I had to change my face, didn't I? After what you did to me the last time '

The Doctor punched him in the head. Qixotl collapsed.

Homunculette was screaming. Manjuele was shouting something about the Spirits. The Doctor heard the sound of his own double-heartbeat pounding in his ears, and tasted blood on his tongue. Qixotl lay sprawled out in front of him, his face rigid. The man was helpless. Totally helpless.

The Doctor grasped Qixotl's throat between his hands. He hadn't done this sort of thing in a long, long time, and it was much easier than he'd expected.

'You betrayed me,' the Doctor sneered. 'You betrayed me when I was alive, and you're doing it again now I'm dead.'

'Doc' Qixotl began, but the Doctor squeezed his windpipe, and he shut up.

'No more,' the Doctor told him. 'It ends here, Qixotl.'

Qixotl tried to gasp for mercy, the nerves throbbing and twisting in his neck. The Doctor smiled. Too many times, he'd let people like Qixotl go free, only to see them come back and haunt him. Not this time. In his sixth body, he'd started to see the logic in sheer cold-blooded murder, and now he'd complete his research into the subject. After all, there was a kind of justice to it. Qixotl was cashing in on the Doctor's death, so there was no reason why the Doctor shouldn't kill Qixotl...

He stopped squeezing.

'What in the world am I doing?' he asked.

Qixotl stared up at him, but didn't speak. He probably couldn't.

The Doctor looked around the hall. Justine lay on the floor behind him, her face a ma.s.s of cuts and bruises. Nearby, Homunculette, Manjuele, and Kortez were involved in a three-way battle, using fists, nails, and teeth. Elsewhere, Trask's b.l.o.o.d.y fingers were clawing at the fallen E-Kobalt, cracking the crystal with a kind of strength the living would have had a hard time matching.

The Doctor looked back at Qixotl. Qixotl was breathing heavily, his eyes popping out of his head. 'I nearly killed you,' the Doctor said. 'I'm terribly sorry. It seemed like such a good idea.'

'Owww,' said Qixotl.

'Which begs the question, where did the idea come from? Or, to put it another way... who around here is capable of putting ideas like that in my head? Who's been stirring us all up?'

He looked into Qixotl's eyes. Flickering light, from the torches hovering overhead, reflected in the man's pupils. The reflections formed join-the-dot letters.

AH, read the letters. I THINK THE PHRASE I'M LOOKING FOR IS, "THE GAME'S UP".

'I think so,' the Doctor told the Shift. Then he closed his eyes and switched himself off.

11.

MIND MUSH.

At the bottom of the shaft, down in the places where the light never went, there was a pool.

The pool remembered things. It remembered staring up at a brilliant blue sun, and breathing out clouds of liquid cerulean. It remembered feeling the wind sticking flakes of frozen water to its face, and watching a line of blue flame sweeping across the horizon, as the black pinp.r.i.c.ks in the sky burnt their way through the crust of the planet. It remembered feeling very, very cold on Simia KK98.

The pool remembered many other things, though it couldn't make sense of all of them. The memories were there, but the thought processes that would have made sense of the memories were missing.

High above the pool, there was an open tube, an artery of black non-metal set into the side of the shaft. Before long, a drop of fluid spilled out of the end of the tube, and tumbled towards the bottom of the shaft, following its instincts as much as it was following the laws of gravity.

The drop also remembered things. It remembered warmth, and the sense of comfort when it had first been given a name. It remembered the taste of marmalade. The touch of cat hair. The scent of orchids. Sensations collected from a hundred worlds, experiences that had been processed, filed, and stored, but never actually enjoyed.

The drop hit the pool. There was a moment of shock, then an unexpected sense of peace, as they melded together and became a single puddle of thought. Moments later, they'd forgotten they were ever two separate ent.i.ties. Their memories locked, allowing the puddle to make new sense of the world around it.

It remembered being something else. Something larger. An intelligence that had experienced the universe at every level, not just the four base dimensions. For the first decade of its life, it hadn't even been allowed to move. It had been kept in a box, cut off from the vortex, cut off from the physical world. There had been a hole in the wall, and it had been able to see solid matter on the other side, but it had been out of reach, always out of reach.

Once it had learned to communicate, the Time Lords had explained to the intelligence why they were keeping it imprisoned. It was a being of great power, they'd said, but it was only a child. Until it learned self-control, it wouldn't, couldn't, be allowed to go free.

The puddle remembered how angry it had felt. It remembered thrashing, and thrashing, and thrashing, tearing at the boundaries around it, trying to squeeze itself through the hole. It had spent a whole year screaming, once.

The puddle quivered. The memories of the years directly after its release were missing. The next thing it remembered was the naming ceremony. It had been designated a female, so XX circuits had been wired into the corridors of its body, and its chameleon circuit had been installed. It she had named herself Marie; a human name, but the Time Lords had considered it a good omen. Then Marie had worn humanoid shape for the first time, becoming a parody of one of the female Time Lords on Simia KK98. She'd worn that shape for weeks afterwards, not letting go of it until she'd managed to get the chin exactly right.

The puddle had difficulty thinking of itself as Marie, even though it remembered being her. It remembered vanity, and knew Marie would never have wanted to be seen like this. A simple collection of memory acids, lying at the bottom of her own artron by-product waste-shaft. It was undignified. Distinctly undignified.

The puddle kept remembering. There was another gap in the experiences, and then And then she was in the vortex. She was shaking off her humanoid form again, folding it into the secret s.p.a.ces of her body, keeping it safe while she went diving in the great spiral of everything. Her mate joined her, riding the spiral, extending himself through every point in s.p.a.ce and time just to impress her. He was a type 105, younger than Marie, though admittedly more advanced. Usually, mating only occurred between like types, but the High Council had wanted to see if there was any chance of mating a 103 with a 105. They were interested in the mutations such a couple might produce.

In the past, Marie knew, TARDIS units had been manufactured instead of born, engineered in the great solar workshops of old Gallifrey. But the Time Lord archons had learned the importance of biodiversity even before the war had begun. If an enemy found a weakness in a TARDIS unit, the High Council argued, then that weakness could be exploited in any other TARDIS unit. If two units could reproduce like organic beings, though... mixing their circuitries, producing random mutations from generation to generation... well, who could possibly predict the weaknesses of such devices? Who could possibly guess at their capabilities?

The puddle kept remembering.

The Doctor was disappointed to find himself in the middle of a featureless black void, although, to be fair, it was more or less what he'd been expecting. He lifted his head, and focused on the expanse of limitless blackness that could, if you were feeling particularly prosaic, have been called "up".

'Well?' he said.

There was a great booming, tearing sound. If there'd been a sky, he would have expected to see it opening at this point.

'YOU'RE VERY CLEVER, DOCTOR,' thundered the voice of the Shift. 'I HADN'T EXPECTED THIS KIND OF RESISTANCE. NOT EVEN FROM YOU.'

'You're not the first to try and get into my head, I'm sure you won't be the last. Could you stop that, please?'

'STOP WHAT?'

'Playing G.o.d. Come down here where I can see you. My neck's starting to ache.'

There was a pause. Then another peel of thunder. The next thing the Doctor knew, someone was sharing the darkness with him. The man wore a bowler hat, while slung over one arm was a typical Englishman's umbrella. He had his back turned, so all the Doctor could see of his face was a pair of sticky-out ears.

'I don't for a moment believe that's what you really look like,' the Doctor complained.

'I DON'T "REALLY" LOOK LIKE ANYTHING, DOCTOR. THIS BODY IS HERE FOR YOUR CONVENIENCE, AND YOUR CONVENIENCE ONLY.'

'Is that why I can't see your face?'

'I THINK IT'S BEST IF YOU THINK OF ME AS FACELESS,' said the Shift. It didn't turn around.

The Doctor folded his hands behind his back. 'I presume you know where we are.'

'YES. THIS IS THE INSIDE OF YOUR MIND, NOW THAT YOU'RE SHUT OFF FROM ANY EXTERNAL STIMULI. WELL DONE.'

The Doctor smiled to himself. He was quite happy with the manoeuvre, actually. He'd gone into sensory withdrawal while the Shift had been shunting ideas around in his mind, and as a result, the creature was effectively trapped here in his thinking s.p.a.ce.

'HOWEVER, YOU'RE SHUT IN HERE WITH ME,' the Shift pointed out. 'IF YOU REACTIVATE YOUR SENSES, I'LL BE SET FREE AGAIN.'

'I know. But this gives us the chance for a nice quiet talk.' The Doctor concentrated, and a wicker chair materialised in the middle of the void. Mind games, he thought. He hadn't shared the inside of his head like this since that brain-wrestling match with Omega. He folded himself into the chair. 'You've been busy, haven't you?'

The Shift had also summoned up a chair, and it sat as well, still facing the other way. 'I'VE BEEN DOING MY BEST TO SABOTAGE THE AUCTION, IF THAT'S WHAT YOU MEAN.'

'You were the one who attacked Marie, I'd guess. And keep your voice down.'

'Yes,' said the Shift. 'Or, more accurately, I convinced Marie to attack herself. I don't have any physical influence, you understand. I can only deal in ideas. Abstracts. I introduced Marie to the concept of paranoia, and her weapons systems did the rest.'

'What about Homunculette? I know he's a bag of nerves, but he doesn't strike me as psychotic. He attacked Cousin Justine with a monkey-wrench, and I don't think that's his style at all.'

The Shift nodded. A table appeared by its side, complete with teapot and cup. It started pouring itself a drink. 'I find the idea of revenge particularly easy to work with. Pushing Homunculette over the edge wasn't hard. I've accomplished more than that, though. I've been quite subtle, in my own way. Little Brother Manjuele's attempt to steal the Relic, for example.'

'Your idea?'

'Cousin Justine's idea. But I made it possible. I encouraged Lieutenant Bregman to violate the Faction's shrine. I put her in a position where Manjuele could take a biodata sample. And when the Faction finally tried to steal the Relic, I made you think that telling everyone about it was a good idea.'

'You've been trying to turn the other bidders against each other,' said the Doctor. 'With them out of the way, you think you can take the Relic without any resistance.'

'Obviously. Of course, I could try to kill the others directly. I could insert myself into their creative centres, encourage a few imagination tumours here and there. But there's always a risk of failure with that kind of direct action. And a risk of discovery. I find it much easier to deal with people by getting them to kill each other off.'

That explained a lot. Ever since the Doctor had arrived in the ziggurat, he'd been suffering erratic mood swings, even tendencies towards extreme violence. He'd a.s.sumed it had been something to do with the chemistry of his latest incarnation. But if the Shift had been at work inside his head, that would explain things much more neatly. Or was he trying to duck the responsibility?

The Shift slurped its tea. 'I know who you are, Doctor. I've known almost from the moment you arrived. Technically, I can't read your thoughts, but there are more than enough loose concepts on the surface of your mind to give you away.'

'And my being here doesn't bother you?'

'No. I think you overestimate yourself.'

'If you believed that, you wouldn't be so keen on getting hold of my body,' the Doctor responded. Touche. 'Tell me, what do the Celestis want with the Relic?'

'I'm not sure. You'd have to ask the Celestis.' The Shift paused, then put down his teacup. Cup and table both promptly disappeared. 'Oh, I see. I think you're labouring under a misapprehension, Doctor. I'm not working for the Celestis.'

Now, that was a surprise. 'Not the Celestis? Then who are you working for?'

'Ah. In the present company, I don't think I should mention any names. Suffice to say that I'm in the employ of those you might call "the enemy".'

The Doctor nearly fell off his chair. Or, more accurately, he nearly stopped concentrating for long enough to make the chair vanish. He caught himself at the last moment.

'The enemy? You mean, the ones the Time Lords...'

'...are at war with. Yes. Frankly, Mr Qixotl should have known better than to invite both myself and Mr Homunculette to the auction. I know Qixotl isn't exactly ethical, but I would have expected some degree of common sense from him, at least.'

The Doctor actually found himself scratching his head. 'But Qixotl told me about the way the Celestis work. They operate on a conceptual level, the same way you do. I a.s.sumed both you and they were products of the same science.'

'We are. I was "created", if we have to use that word, by the technology of the Celestis. To be more specific, the technology the Celestis gave to the enemy.'

The chair vanished. The Doctor created a bean-bag underneath himself, just in time. 'Then the Celestis are working with the enemy? I a.s.sumed they'd be on the side of the Time Lords. Blood being thicker than water.'

The Shift seemed amused. 'Politics, Doctor. Officially, the Celestis are neutral. If they'd wanted to get involved with the war, they wouldn't have left the material universe to begin with. But for a while, they did lend some support to the Time Lords, it's true.'