'And then the Time Lords started losing,' the Doctor murmured, more to himself than to the Shift.

'n.o.body likes to be on the losing side. Besides, the Time Lords aren't nearly interesting enough for the Celestis' liking. Think of it this way. You're a carbon-based life-form, the Krotons are tellurium-based life-forms, and the Celestis are idea-based life-forms. They need new ideas to survive, but the High Council hasn't had a decent new idea for thousands of years. The Celestis are starting to side with my employers, largely because my employers are so much more... how shall I put it? More imaginative. More dynamic.'

The Doctor slapped his forehead. Of course. Qixotl had said that some of the Celestis were going over to the enemy, but so much had been going on, he'd missed the significance of it.

'My employers felt it necessary to stop the High Council obtaining the Relic,' the Shift continued. 'In fact, the Celestis weren't happy about me attending the auction at all. They have a personal grudge against you, Doctor. They wanted your body for themselves.'

'Then why didn't they send an agent?' the Doctor asked. The Shift didn't answer. The Doctor suddenly realised what he was missing. 'Trask.'

'Yes. To an extent, Trask is a product of the same science as myself. But I'm an intelligence without a physical form, and Trask is an intelligence forced back into back into a physical form. The Celestis have agents all over the material universe. Thousands of corporeal beings, each one bearing the Celestis' mark. When they die, their minds are transferred to the Celestis' own realm. They call it Mictlan, I believe.' a physical form. The Celestis have agents all over the material universe. Thousands of corporeal beings, each one bearing the Celestis' mark. When they die, their minds are transferred to the Celestis' own realm. They call it Mictlan, I believe.'

Mictlan. The land of the dead, in South American folklore. The Celestis were getting some of their ideas off humans, then. 'That's tantamount to soul-stealing,' the Doctor protested.

'True. Trask was a Celestis agent while he was alive. The Celestis recorporated him specially for this auction. Although, from what I can gather, they didn't bother telling him what he was actually bidding for. They felt he'd be an appropriate choice to attend the sale of your body, bearing in mind that you were the one who killed him in the first place.'

'Was I?' The Doctor tried to look sheepish. 'I'm sorry, I had no idea.'

'It was a long time ago. Incidentally, I did plant a reminder of you in Trask's mind, when you arrived. I changed his memory of the way he died, as well. Just to make it a little more dramatic. I was hoping he'd deduce your ident.i.ty by himself and try to kill you out of spite. Obviously, I wouldn't have expected him to succeed, but it might have distracted you for a while.'

'And Qixotl? A minute or two ago, I remembered meeting him before somewhere, but now I can't quite recall the details. Did you plant those memories, too?'

'I can't plant memories, Doctor. I can only adapt them. Memories can be reshaped by ideas, as easily as emotions can. As for your past acquaintance with Mr Qixotl... well, that's between you and him.'

The Doctor stood. The bean-bag, forgotten, faded into nothingness behind him. 'I think I've heard enough.'

The Shift stood, as well, and allowed its chair to slip away into the void. 'Curious. You sound like you're expecting victory. Might I remind you, you can only keep me here as long as your senses are closed off to the outside world.' The Shift considered its next words carefully. 'Besides which, you're a.s.suming I can't kill you now.'

'Even if you could, you wouldn't. If I die while you're inside my mind, you'll be stuck here forever.'

'Not at all. Your body is destined to end up inside Mr Qixotl's casket, whatever happens. Logically, I'll only remain locked inside your head until he sells the Relic. When the buyer tries probing your dead brain, as any buyer inevitably will, I'll be able to make my escape.'

The Doctor frowned. 'I'm sorry, this is getting horribly convoluted. I can't die now. I know I'm destined to go through more biodata changes before my death. In this regeneration, my biodata isn't valuable enough to go to all this trouble for.'

The Shift seemed irritated by this trifling point of logic. 'Supposing I kill you now, Doctor. Supposing Trask collects your body, and the Celestis recorporate it, to use it as one of their agents.' The Doctor actually shivered at the thought. The Shift went on. 'The recorporated Doctor could pick up all the biodata the Time Lords think is so valuable, before it dies a second second time. Then, somehow, it finds its way into Qixotl's possession and ends up here in the vault of the ziggurat, ready to be sold again. Causality is satisfied.' time. Then, somehow, it finds its way into Qixotl's possession and ends up here in the vault of the ziggurat, ready to be sold again. Causality is satisfied.'

'I hate this sort of nit-picking,' the Doctor muttered. 'All right, I accept I'm mortal. But it's a moot point. You can't kill me, not here. You don't have the power.'

'Doctor, I've been ordered to secure the Relic for my employers, and that's what I intend to do. Don't stand in my way. Leave in your TARDIS as soon as you can. This is a lost cause. You have no place here. You know that's the truth.'

The Doctor thought about it for a moment.

'Yes,' he said, in the end.

The Shift seemed surprised, even though the Doctor couldn't see its expression. 'Yes? Yes what?'

'Yes, I agree. I shouldn't get involved.'

'Then you'll let me go?'

'I don't exactly have a choice.' The Doctor sighed, with well-rehea.r.s.ed weariness. 'I don't like leaving my remains in your hands, but you are are talking about events in my future. The war doesn't affect me, and it never will. Not while I'm alive. I'm not going to stay here with you for the rest of my life, not if I should never have become involved in the first place. So, you can leave. Now. Before I change my mind.' talking about events in my future. The war doesn't affect me, and it never will. Not while I'm alive. I'm not going to stay here with you for the rest of my life, not if I should never have become involved in the first place. So, you can leave. Now. Before I change my mind.'

The blackness of the void split open, as if it had been unzipped from top to bottom. On the other side of the opening, the Doctor could see the conference hall of the ziggurat. The other representatives stood motionless, frozen in poses of mindless aggression. No, not frozen, the Doctor reminded himself. They were moving, but very, very slowly. Here inside his mind, events were occurring at ten thousand times their normal speed. In "real" time, the discussion with the Shift had taken a split-second.

For a moment, the Shift stood quite still, facing the light from the outside world. Then it disintegrated, becoming a cascade of concepts, glistening ideas that looped and whirled as they headed for the opening. The Doctor made sure every last notion was safety out of his head before he zipped the darkness up again.

He'd been forced to let the Shift go. He hadn't been able to confine it permanently, not without confining himself along with it. But then, he hadn't been prepared. And whatever he'd said, he didn't intend to let anyone walk off with his old bones, not without a fight.

The Doctor concentrated, and willed new shapes to materialise out of the void. He had to refurnish his mind. Next time, he'd be ready.

A few moments ago, the Doctor had mumbled something that had sounded like "sorry". The Doctor had this thing about taking life, Qixotl remembered. It made him uneasy, for some reason. Just like him to apologise before doing someone in.

Qixotl closed his eyes, and waited for the killing blow.

And waited.

And waited.

Nothing happened, and it happened in style. Around him, the sounds of senseless violence had died down, becoming nothing more than a bunch of awkward scuffling noises backed up by muzak.

Mr Qixotl opened up one eye. Nothing blinded it or tried to gouge it out, so he opened the other one.

The Doctor stood over him, an expression of smug satisfaction plastered across his face. Nearby, Cousin Justine lay on the floor, looking lost and bewildered, her skin covered in sc.r.a.pes and bruises. Next to her was a pile of limbs which, once disentangled, would almost certainly prove to be made out of Homunculette, Little Brother Manjuele, and Colonel Kortez. On the other side of the shattered table stood E-Kobalt, its head going round and round and round and round, while Trask was his usual less-than-human self.

'And I hope you're all thoroughly ashamed of yourselves,' said the Doctor. It sounded like he was delivering the punchline to a very strange and complicated joke.

Cautiously, Kortez struggled free of the man-heap. Homunculette followed his example. Manjuele was the last one on his feet.

'Everything's changed,' Cousin Justine observed, as she picked herself up and delicately dabbed some of the blood off her chin. 'You can feel it. It's...'

'Less tense?' suggested the Doctor. 'Well, less tense than you might expect, bearing in mind who's here.'

'Whoah,' said Qixotl. 'Whaah. I mean, what...?'

'We've all been taken for a ride,' the Doctor explained. 'The thoughts we've been having aren't entirely our own. The Shift has been trying to sabotage the auction.'

'Not true,' said Trask. 'You. You killed me.'

The Doctor spun around. 'Really? How?'

'You...' began Trask, but he didn't seem to know how to finish. 'I. I remember. Water... no. There was...'

He lapsed into silence. The Doctor nodded. 'Exactly. The memories have been adjusted by the Shift. Mr Qixotl?'

Qixotl squirmed backwards, in case the Doctor had any more murderous inclinations. 'It's not my fault,' he whimpered.

The Doctor raised both eyebrows. 'You knew who you were inviting. You should have researched your clients' abilities more thoroughly.' Behind the Doctor, the Kroton's head was spinning faster than ever, but the thing didn't speak. Qixotl wondered if it was having some kind of a fit.

'Who, exactly, did Mr Qixotl invite?' Justine asked.

For once, Homunculette grunted his approval. 'Good question. Who was the Shift working for?'

'A power quite familiar to you, Mr Homunculette,' said the Doctor.

'You mean...?'

The Doctor nodded. Qixotl watched Homunculette's face. In the first five seconds alone, it cycled through sixteen distinct shades of purple. The Time Lord turned to Qixotl, fortunately too speechless to swear.

'Sorry,' squeaked Qixotl.

'You invited them them here?' screamed Homunculette. 'You actually wanted me to sit down at the table with... with...' here?' screamed Homunculette. 'You actually wanted me to sit down at the table with... with...'

'Yes, he did,' the Doctor concluded, helpfully.

Qixotl felt his pulse trying to leap out of his wrist. 'Now, listen, let's not get excited. It's like I told the Doctor here, business is, er, business. I can't make moral judgements about my clients, y'know?'

Homunculette lunged. Qixotl curled up into a ball, and covered his face with his arms. n.o.body actually hit him, though, so after a few moments he risked peering out from between his hands. The Doctor stood in front of him, restraining Homunculette with a single finger. 'You're still angry,' the Doctor said. 'Even with the Shift out of your system, you're angry, and you're upset. You have to fight it. This is what the Shift wants us to do.'

'How d'we know s'not in his head now?' asked Manjuele.

Homunculette glared at the Paradox cultist, but the Doctor shook his head. 'The Shift works best when it's dealing with subconscious thought processes. Now we're consciously aware of what it can do to us, it shouldn't be able to manipulate us so easily. That's my guess, anyway.' The Doctor looked around the hall. 'Are we missing somebody?'

Qixotl looked around, too. The Doctor had a point. There was definitely something missing from the room. It was as if a major piece of furniture had vanished, something so large you didn't immediately notice when it was gone.

'The Kroton,' said Cousin Justine.

That was it. E-Kobalt had vanished. He'd probably shambled off out of the room while Qixotl had been cowering from Homunculette; let's be honest, thought Qixotl, it's not easy to miss a lump of matter that big sneaking away, unless you've got other things on your mind. 'He was acting funny just now,' he told the others. 'His head was going mental.'

The Doctor looked grim. 'Krotons have some fairly rigid ideas about how to deal with aliens. Ideal material for the Shift to work with.'

'Not important,' said Trask. 'Shift's gone. Let it go.'

The Doctor's face became a shade grimmer. 'The Shift won't leave until it's secured the Relic. It'll take the City apart brick by brick, if it has to.'

Qixotl sc.r.a.ped himself off the ground. 'Not a problem. It can't damage the ziggurat, right? The defences can take out any weapons system it can chuck at us, no trouble. We're safe.'

The Doctor looked still grimmer.

'The defences,' he said. 'I knew there was something I had to tell you. Qixotl... if, theoretically, somebody had shut down all the City's defences, how long would it take to reset them?'

'Couple of hours, probably. It's a delicate kind of system I'm running here. Er, why?'

'Oh dear,' the Doctor said. The next thing Qixotl knew, the Time Lord was hurling himself towards the exit.

Kathleen didn't move.

Kathleen didn't move, again.

Kathleen persisted in not moving.

Sam was, quite frankly, getting sick of this. Tending to the sick was one thing, but she wasn't actually doing anything except sitting at the end of the Lieutenant's bunk, waiting for the woman to wake up screaming or have an interesting muscular spasm or something. Once, a minute or two ago, Kathleen had murmured the word "dead" in her sleep, but that had been the high point so far.

An alien sauntered past the doorway of the guest room. Its head was gyrating, its arms were wobbling from side to side, and it was making an odd warbling noise as it moved.

Well, it was novel, at least.

That was the problem with this kind of job, thought Sam. Time-travelling was great, yeah, but there was a h.e.l.l of a lot of waiting around involved. The Genetic Politics Genetic Politics book had vanished again, so she didn't even have anything to read. Next time I leave the TARDIS, she told herself, I'm packing a copy of book had vanished again, so she didn't even have anything to read. Next time I leave the TARDIS, she told herself, I'm packing a copy of Mizz Mizz. For definite.

The Doctor's head popped through the doorway, and peered around the guest room. Involuntarily, Sam stood to attention.

'Have you seen a Kroton come this way?' the Doctor asked, somewhat urgently.

'Don't know. Is a Kroton a big silvery-white thing that looks like it came out of a fondue set?'

The Doctor looked surprised. 'Yes, I suppose it is.'

Sam jerked her thumb. 'It went that way.'

He'd vanished before she'd even finished the sentence. Sam looked back at Kathleen. The Doctor was in one of his "quick, let's save the world" moods, so there was probably going to be trouble.

Kathleen would be all right on her own, wouldn't she? Just for a few minutes?

Sam caught up with the Doctor at the bottom of the stairway, the one where Kathleen had offered her the funny cigarette. Catching him wasn't hard; he had legs like a cranefly, but Sam was a born runner, three miles a day, no excuses. She put her hand on the Doctor's shoulder, and the Doctor jumped.

'I'm coming with you,' Sam told him.

'You don't know where I'm going.'

'Stop picking holes.'

The Doctor looked mildly exasperated. 'We have to stop the Kroton reaching its ship. Luckily for us, they don't move very fast. Not in their high-gravity bodies, anyway.'

'Doctor?'

Sam and the Doctor both turned. The Colonel stood at the far end of the corridor, his face as rigid-looking as ever. He saluted, stiffly, then started marching in their direction.

The Doctor went from "mildly exasperated" to "increasingly exasperated". 'Colonel, now isn't the time '

'Doctor. I know you now. You understand.'

'Understand? Understand what?'