'I don't know. Really, I don't. I left Dronid before the fighting started. I'm telling the truth, I promise.'

'THERE-IS-AN-OB-VI-OUS-CON-CLU-SION,' the four Highest Brains rumbled. 'TIME-LORD-WEAPONS-TECH-NO-LO-GY-IS-IN-ADVANCE-OF-OUR-OWN. WE-MUST-STU-DY-THE-GE-NE-TIC-AR-MA-MENTS-OF-THE-SPE-CIES. WEAPONS-SUCH-AS-THESE-MAY-GIVE-US-A-DE-CIS-IVE-AD-VANT-AGE-O-VER-THE-ME-TA-TRAX-I.'

E-Kobalt knew what they really meant, of course. The Krotons were already winning the war, but new weapons were always useful. Once the Metatraxi had been defeated, the Absolute would expand beyond the Quartzline Front, and it was bound to run into other hostile races along the way. 'What-are-your-instruc-tions?' E-Kobalt asked.

'RE-TURN-TO-THE-FIFTH-LATT-ICE. FROM-THIS-MO-MENT-ON-THE-ME-TA-TRAX-I-ARE-NOT-YOUR-CON-CERN. YOUR-MISS-ION-IS-TO-LOCATE-A-MEM-BER-OF-THE-TIME-LORD-MI-LI-TA-RY. THE-DOC-TOR-WOULD-BE-AN-I-DE-AL-SUB-JECT-FOR-AN-AL-Y-SIS.'

E-Kobalt acknowledged the orders, and started weighing up its options. If it had to track down a Time Lord warrior, Dronid would probably be the place to start. Even if the battle had ended by the time the Fifth Lattice got there, the Time Lords might have left some of their dead or wounded units behind.

And the Time Lord must have guessed what E-Kobalt was thinking, because it squealed: 'You won't be able to get near Dronid. You won't be able to. The High Council's going to sterilise the planet as soon as the fight's over. It'll be off limits for years. You won't be able to make planetfall. I'm serious.'

The tendril clenched. The Time Lord yelped. 'YOU-HAVE-YOUR-OR-DERS,' the Highest Brains told E-Kobalt. 'RE-TURN-TO-THE-FIFTH-LATT-ICE. WE-WILL-BE-GIN-A-FI-NAL-BI-O-LOG-IC-AN-AL-Y-SIS-OF-THIS-TIME-LORD-UN-IT. YOU-WILL-BE-NO-TI-FIED-OF-AN-Y-DIS-COV-ER-Y-THATMIGHT-a.s.s-IST-YOUR-MISS-ION.'

'Er, what does "final biological a.n.a.lysis" mean?' asked the Time Lord. But the tendril was already lifting the alien high above the floor of the cavern, and new limbs were sprouting from the crystalline walls, scalpel-pincers poised, bio-intake tubes at the ready.

E-Kobalt turned, without a word. It wasn't the Kroton way to salute. The Commander of the Fifth Lattice started the three-day trek back to its dynatrope, its objectives clear, its mind already formulating a search strategy.

Behind it, the Time Lord unit began to scream.

10.

WHAT IS IS AN IDENt.i.tY CRISIS, ANYWAY? AN IDENt.i.tY CRISIS, ANYWAY?.

The Doctor ran his fingertips along a strand of the web. It was sharp, sharp enough to give him a wound the size of a papercut, and it shivered when he let go of it. Traces of life, the Doctor decided. He took another look at the web's design. Clearly a retinal pattern, stretched across the top of the stairway that led down to the lowest level. Before he'd shut down the security systems, it probably would have responded much more aggressively. He imagined it wrapping itself around his flesh, cutting its way to the bone. Now he'd taken all the systems off-line, the web was dying.

He could have been more selective, of course. He could have only switched off the systems that threatened Sam and her new companion, but that would have taken time. So he'd deactivated the lot, from the roof to the vault. Presumably, Qixotl's damping fields were off-line now, as well. The Doctor hoped no one would upset E-Kobalt too much.

He reached into his pocket for a penknife, but the knife failed to materialise. He was mildly annoyed by that. Perhaps it was the stress; according to old Yeltstrom, you couldn't be at one with your pockets if you weren't entirely calm. The closest thing to a knife he managed to find was his sonic screwdriver, and the mark one version, to boot. He couldn't remember which features he'd built into the mark one, so he pointed it at the web, pushed the trigger, and hoped for the best.

The web began to shrivel, the strings blackening and dropping to the ground like pieces of old fettucini. Eventually, there was a hole in the web big enough for him to climb through without injuring himself.

He had to cut through another three of the retina webs before he reached the lowest level. The floor there was covered in mulch by the time he arrived. The slabs had been pushed aside, torn from the ground by sick-looking growths that reminded the Doctor of leftover spleens. Now the systems were down, the growths were starting to rot, filling the atmosphere with the scent of offal.

Sam lay on her back in the undergrowth, her body wrapped up in tendrils of crispy black bioma.s.s. The creepers had died and calcified, holding her limbs in stiff, unnatural positions. Her eyes were wide open, although her pupils were rolled up under the lids. Scattered around her body were the corpses of things the Doctor really didn't care to look at too closely.

He crouched down by Sam's side, then tried to pull her into a sitting position. The tendrils snapped as soon as he put pressure on them. Sam made a faint moaning noise, and her head lolled forward.

The Doctor brushed the back of his hand against her face. 'Sam? Sam, it's over. You can wake up now.'

Her pupils rolled back into place. Two blurry green eyes focused on the Doctor. He smiled encouragingly.

For a moment, Sam didn't respond. Then: 'I dreamt something,' she said.

Ah. Now, thought the Doctor, is this going to be an insignificant meaningless delusional dream, or a portentous prophetic dream with serious ramifications on the cosmic scale?

'I was a heroin addict,' Sam went on. Then she shook her head, a bit groggily. 'No I wasn't. I'd taken heroin, but I wasn't an addict. Is that possible?'

The Doctor felt faintly embarra.s.sed. 'I don't know. I'm hardly an expert.'

'Everything was different. I remember getting drunk a lot. I never get drunk, do I? Oh, G.o.d. There were other things. This boy. I was fourteen. No, fifteen.' Sam was shaking, the Doctor noticed. 'It was another life. A whole other life. I mean, I was me, but I was someone else. I never met you. You know the first time I saw you, I was running away from those dealers at Totters Yard? I remember, it was different. They were my friends. No, they weren't my friends, but I used to... oh G.o.d. Oh G.o.d, I don't believe this.'

The Doctor rested his hand on her cheek. Lying to her might be the best idea, he decided. 'It was only a dream, Sam. Dreams only mean what we want them to mean.'

'But it didn't feel wrong. You know? It felt like it was the way things were supposed to be. And when I woke up, and you were there, I... it didn't feel right any more. It felt like I wasn't supposed to be here. Like I was supposed to be back in London. King's Cross. I've hardly ever been to King's Cross. Why should I dream about it like that when I've hardly ever been there?'

The Doctor wondered what he should say. To an extent, she was probably right. By taking Sam off in the TARDIS, he'd changed her timeline, and by a.s.sociation, the timeline of her whole species. But he'd taken risks like that a billion times before, nothing bad had happened so far. Well, nothing very bad. What was different this time?

'Who am I?' Sam asked, between breaths, and the Doctor suddenly realised she was crying. Sort of. Shallow, half-hearted sobs, as if she knew she ought to be upset, but wasn't sure how to go about showing it. 'Who am I supposed to be?'

The Doctor put his arm around her. He didn't have an answer.

Before Sam could say anything else, there was a muted gurgling sound from somewhere nearby. Sam stopped crying in a second. The Doctor felt her limbs go stiff in his arms. Slowly, he disentangled himself from her, and stood.

A few feet away, a second figure lay among the kidney plants. It was curled up like a foetus, and the similarity didn't end there. Its eyes were wide open, but then, the Doctor doubted it had any eyelids. It was the creature he'd seen on the pixscreen in the security centre. The antibody's umbilical cord had withered away, and without the City's systems to support it, it had fallen to the ground, ready to die.

'What is it?' asked Sam. Her voice wasn't much more than a squeak. Mercifully, she couldn't see the thing from where she was sitting.

'Nothing,' the Doctor told her, not taking his eyes off the antibody. 'Nothing at all.'

The antibody turned its soft, swollen head. Two huge black eyes stared up at the Doctor from the undergrowth.

It gurgled again. Three syllables. The Doctor wouldn't have identified the sounds as words, if he hadn't been able to see the antibody's lips moving.

'It's-not-fair.'

Without a word, the Doctor raised his sonic screwdriver. The antibody followed the movement of his arm. It stopped thrashing its little stunted limbs.

'It's-not-fair.'

The Doctor pressed the trigger.

The cells of the antibody had already started to collapse in on themselves. The screwdriver accelerated the process. The creature's skin wrinkled, then turned black, shrinking and hardening across its bloated body. Tumours blossomed across its cranium. The eyes sank into the underdeveloped skull.

Eventually, there was nothing left of the antibody but a husk. The Doctor lowered the screwdriver, but didn't turn away.

'Doctor?'

The Doctor didn't move.

'Doctor? What's going on?' Behind him, he heard the rustling of dried bioma.s.s as Sam tried to pick herself up off the floor. He felt his fingers tightening around the shaft of the screwdriver.

'Alien bodies,' he whispered.

'That's the sonic screwdriver, isn't it? I thought it got trashed by the Zygons.'

The Doctor nodded. Sam was back to normal already, if you could ignore the catch in her throat. Curious as ever, always ready to ask awkward questions about the technical details.

'That was the mark five screwdriver,' the Doctor muttered. 'This is the mark one.'

'The mark one?'

'Yes. It was destroyed centuries ago.'

A pause. 'Then how...?'

The Doctor motioned for her to be silent. He didn't feel up to explanations right now. In front of him, the remnants of the antibody began to liquefy. 'It's a Time Lord tool. Time doesn't work the same way for Time Lord tools.' He turned, at last, and saw that Sam had managed to stand, although her legs didn't look too stable. 'We have things to do.'

Her eyes widened. 'Kathleen!'

'Where is she?'

Sam pointed to a nearby wall. The wall was pink and organic, obviously not an original part of the vault's architecture. The material, like everything else here, was in a state of decay.

The Doctor took one last look at the antibody before it melted away into nothingness. Then he raised the screwdriver again, and set to work on the wall.

The labyrinth had started to stink of old meat. Little Brother Manjuele kicked a couple of the plants in his path as he made his way along the tunnel, and they exploded on impact, spewing their insides out all over the floor. Manjuele grinned. Some of the plants had Bregman's face, so he got a kind of buzz out of seeing the b.i.t.c.h's head burst open over and over again. It wasn't anything personal. Back in Little So Paolo, he'd seen some of his best friends broken by uniform s.l.u.ts like her. Electric batons on the streets, matchsticks under the fingernails in the police cells.

The ceiling split open, and something dropped through it, stopping a couple of centimetres in front of his face. He jumped back, but it turned out to be another potato-shaped copy of the UNISYC woman's head, dangling from a thick pink tendril. It looked dead, so Manjuele punched it aside. If he'd guessed right, the vault had only grown the plants to make Bregman feel bad about herself.

Jesus, that was pathetic. Was that all it took to make the b.i.t.c.h go laa-laa? The vault was going to have to do a h.e.l.l of a lot better than that if it wanted to stop him. Come to think of it, as soon as he'd got here, the labyrinth had started dying. Maybe the vault had given up, thought Manjuele. Maybe it knew he was too tough a customer to send over the edge like that.

Maybe. h.e.l.l, you never knew.

At last, he reached the end of the pa.s.sage. It opened out into a wide chamber, the wall opposite made of solid brick, although spores had squeezed themselves out of the cracks between the blocks. In the middle of the room, on the other side of a garden of dead flesh-flowers, was a silver casket.

Manjuele laughed out loud. The Relic. Getting to it had been easy, real easy. He stepped out into the chamber with his biggest and baddest grin on his face. The grin felt funny, though, stretched across these mouth muscles.

'Kathleen?' said a voice.

Manjuele stopped grinning, and whirled around.

To his left, the chamber ended in a wall of rotting pink bioma.s.s. The wall had been cut open down the middle, and two figures stood in the opening. One was the guy in the green velvet jacket, the one Justine had told him was a renegade Time Lord. The other was the blonde who'd arrived with him. They were taller than Manjuele remembered, though. The man seemed huge, and even the girl looked like she could put up a good fight. It took the Little Brother a second or two to figure out why. He was looking through Bregman's eyes now, and Bregman was shorter than he was. So, everything looked bigger.

The girl stumbled forward, her arms outstretched. 'Kathleen. I was worried. I thought the antibodies had got you.'

'Uh,' said Manjuele.

The girl wrapped her arms around him. Manjuele flinched. 'It's all right. The Doctor's here now. We're going to be fine.'

'Doctor?' said Manjuele.

The girl let go of him. 'He says they're ready to start the auction. We'd better get moving.'

Manjuele watched the Time Lord. His eyes were fixed on the casket in the middle of the vault. He looked like he'd been hypnotised. Every few seconds, he'd shake his head, like that'd bring him back down to Earth.

'We gonna take the Relic with us,' Manjuele announced.

The girl looked concerned. 'You think we should?' She turned to the Time Lord again. 'Doctor?'

The Time Lord stopped staring at the box. 'I'm sorry?'

'We gonna take the box,' Manjuele said. He wondered what Bregman would have said, in a situation like this. 'It's, uh, in the best int'rests of Earth. We gotta... we've got to make sure the aliens don't get their hands on it. Hands. Tentacles. Whatever they got.'

The girl blinked at him. 'Kathleen? Are you all right?'

'Uh. Yeah. No prob.'

'Little Brother,' said the Time Lord.

Manjuele twitched. A dead giveaway.

The Time Lord nodded. 'I thought so. You look like you're not used to manipulating that face. Sam. Move away from him.'

'Him?' The girl looked Manjuele up and down, taking in the details of his skinny little female body. 'Doctor...'

'Move away, Sam.' The Time Lord stepped forward. Manjuele reached for his pocket, in search of his knife, then remembered the knife was in the pocket of his real body, back in the shrine. The Time Lord kept advancing, but Manjuele stood his ground. He wondered if he could fight the guy off in a body this pathetic. 'It's not Kathleen. It's one of the Paradox cultists. He's operating Kathleen's body by remote control. One of the Faction's nasty little rituals.'

'Don' come near me,' Manjuele warned him. The words sounded all wrong, coming out of Bregman's mouth.

The Time Lord stopped. 'It's all right. I'm quite close enough now. Tell me, do you know what an exorcism feels like? The process is quite simple, really.'

Manjuele shook Bregman's head. 'Don't treat me like that. Not stupid, hokay?'

'You believe in the Spirits of the Faction, don't you?'

'Don't give me that. I don't wan' hear that.'

'If you believe in the Spirits, you should believe in exorcisms. Unless, of course, you don't have any real faith in the Spirits at all. Sometimes I wonder how much your "family" believes its own propaganda. I'll tell you what I'm going to do, Little Brother. I'm going to put something into Kathleen's head. A sort of a telepathic wake-up call. And you're going to leave. I'm afraid it might hurt quite a bit.'

Manjuele tried to force a grin, but Bregman's face wouldn't respond. He was protected from telepathic attack, Justine had told him. One of the family's little perks. 'You try it, Time p.u.s.s.y. You try it.'

'You're not protected,' the Time Lord went on. 'You see, I've met you people before. I know where the cracks are in your defences. My telepathic abilities aren't particularly advanced, but I think the two of us together should be able to do you some damage.'

He looked to one side. Manjuele followed his gaze.