'I don't think they'd mind, being buried here,' said the Doctor. 'And even if we take them home later, I'll always have a place to... remind me.'

Kitig looked at him, looked at the butterflies, the sorrow in his face, and could no longer believe even the possibility that he could be evil.

'Doctor,' he said aloud, as they returned through the incongruous panelled door to the console room. 'I think we should be truthful with one another.'

The Doctor looked up, met Kitig's eyes for a moment. 'You know who I am?' he asked after a while.

'Yes. But from what I've seen so far, I don't believe that you deliberately set out to destroy our people. It seems more that you are protecting your own.'

The Doctor made that strange bobbing motion of the head that Kitig knew meant he agreed. 'Not my own, exactly,' he said. 'But sort of. I've spent more time with them than I have with my own and there are some people who say... Oh never mind. The point is, yes, your universe is the unstable one. It shouldn't exist. But I know I can't expect you to accept that.'

They'd reached the console now. The Doctor flicked a switch, set a dial, and the time rotor began to move.

'I believe it,' said Kitig quickly. 'It would explain many things. The whole existence of Paratractis, its history, is a paradox. A series of impossibilities. Nonetheless, I exist. My family exists. Or ' he hesitated ' has the potential potential to exist. You can't deny that.' to exist. You can't deny that.'

The Doctor moved away and sat down, using a piece of furniture for support in the way bipeds often did. He was moving his head from side to side: the gesture obviously indicated discomfort. 'That's why I didn't want Sam to let you aboard the TARDIS,' he said. 'You see, you'll continue to exist now, even if we succeed and everything else you know is gone.' He looked up. 'You may never go home.'

Kitig remembered the distant horizon of the butterfly room. The blue sky. The sunlight. This machine was as huge as a planet, at least. It travelled in time and space as readily as Kitig could gallop down a street. The Doctor owned this machine, this power: if he said something about the status of time, of reality, then his judgement was likely to be correct.

'I should try to stop you,' he said at last. 'But I can't believe you to be evil. And if you aren't if you're telling the truth '

He broke off. Was Was the Doctor telling the truth? the Doctor telling the truth?

'I know,' said the Doctor softly. 'I don't believe you to be evil, either, if it's any help. But I can't let that stop me from doing what I know to be absolutely necessary. I'm sorry.'

Kitig closed his eyes.

There was a thud. The ground shuddered. Kitig smelled burning insulation, opened his eyes, and saw smoke rising from the console, the Doctor dancing around, pulling at chains, pushing switches. One of the screens lit up, showing the African plain: golden grass, some animals, a stand of trees.

'Well,' the Doctor said, solemnly. 'This is it.'

Kitig took a couple of steps closer to the screen, saw that the aspect of the plain was very different. The volcano was different: smaller, more neatly conical. A trail of hazy smoke drifted through the sky from its summit. In the foreground there was a lake, only yards from the TARDIS, with a narrow white beach. When the Doctor turned the scanner around to look inland, there were stands of tall trees, separated by scrub and grass.

'We're in a different part of the continent,' suggested Kitig.

'No we're not,' said the Doctor, checking the reading from a brass dial on the console. 'This is the same place. We haven't moved at all in space, relative to Earth. But we've travelled back in time.'

Kitig peered at the console, but the figures were incomprehensible to him.

'How far?' he asked.

The Doctor flicked a switch on the console. 'Just over a million years.'

The TARDIS door opened, and the Doctor started towards it.

'I'm going to find out what's happening,' he said over his shoulder, baring his teeth in a brilliant smile. 'Aren't you going to join me?'

Kitig started after him, wondering why the Doctor was so keen that he should go with him this time, when he had been so anxious to avoid it on their last landing.

But as soon as he stepped out of the TARDIS doors, he knew. He could smell them.

Tractites.

Was the Doctor wrong? Had they come back to Paratractis after everything that had happened? He looked around, sniffed, trying to find visual and olfactory evidence of his world.

Nothing. Just the grass, the animal dung, the distant snows of the volcano and the even more distant sea.

The same world as the one they had just left: pre-civilisation.

But he could smell his people.

And something else. Something alien electrical Dangerous.

'Doctor,' he said.

The Doctor had walked down to the beach, was staring out over the lake at the volcano.

'Doctor, there are Tractites here. I can smell them.'

The Doctor nodded.

'Do you want me to try to find them?'

A pause. Then: 'There won't be any need, Kitig. If you have a look across to the other side of the lake, you'll see that they already know about us.'

Kitig followed the Doctor's gaze across the calm blue water, and saw something that frightened him more than anything that had happened so far.

There were Tractites, yes, but the tiny figures were dressed in some kind of body armour, black and gleaming like angry beetles. Kitig saw the glint of machinery, the long barrel of something that looked like an energy weapon.

The barrel tracked round until it was levelled at them, across the kilometre or so of water.

'No!' shouted Kitig.

Tractites didn't kill Tractites. Unless there was extreme provocation, Tractites didn't kill anyone. But The water of the lake boiled, and the world around Kitig exploded into fire and light.

CHAPTER 17.

'Living, not eating.'

Sam opened her eyes at the sound, saw a man standing over her.

Not a man.

Shaggy hair. A sloping forehead. Animal eyes.

A habiline.

'Waking.'

She heard the grunt, saw the hand gesture, a rapid twisting of fingers against the darkening sky. The TARDIS must be translating for her The TARDIS. The Doctor. The alternative universe. Paratractis. Jacob.

Sam sat up, felt a powerful hand push her back down again.

'Keep still. Danger. Other.' His hands moved in time with the words. In fact, there were no words, only undifferentiated grunts.

Sign language.

'What other?' she asked, whispering.

'Keep silent. Other.'

Sam swallowed. Was 'other' Jacob? What had happened?

She looked around, saw dark shapes crouching in the grass. The sun was low, and the slopes of the volcano were stained with a red evening light.

She became aware that she had a very bad headache, and that her neck was sore.

Movement. A crackle of grass, a thud. Grunts, bodies jumping.

Sam sat up again, and this time no one stopped her. Her habiline was standing guard over her, a stone axe dark in his hand. She saw a white figure moving, heard a voice cry out.

'No! You can't ' Jacob's voice.

And Jacob was there in front of her, being held in place by two habilines. He struggled, then saw Sam. 'See? They try to kill you. Humans always try to kill you.'

Sam stared at him, bewildered. 'I think they just misunderstood what we were doing. We hurt one of them.'

Jacob giggled, an odd, undignified sound. It made Sam uneasy for some reason.

'Not kill,' said the habiline with the axe. 'Choose.'

Choose what? thought Sam.

He pointed at Jacob. 'Hurt people.' At Sam. 'Not hurt.' At Sam again, then at Jacob: then looking at Sam. 'Choose. Kill.

Not kill.'

Sam felt the blood drain from her face as she realised.

They wanted her to tell them whether Jacob should be killed or not.

If she said 'kill', they would kill him. But if she said 'not kill'...

They might kill both of them.

Depending on what they thought was going on. Depending on their social rules, which she didn't know.

She hesitated, then pointed at Jacob. 'Mine.'

'What are you talking about?' said Jacob.

'Yes. Yours,' said the habiline. Sam decided to call him Axeman. 'Kill. Not kill.' He raised his axe, not far enough for a killing blow, but just far enough to be threatening.

Sam stood up, said slowly. 'Let him go.'

The habiline looked at her, then looked at the two others holding Jacob. They let him go.

'Thanks,' he said, breathing fast, his eyes moving nervously. 'Look, I '

' was only returning the favour,' finished Sam for him. She smiled brightly. 'Don't worry, I guess I've just got more practice in this sort of thing than you have.'

Jacob grinned back. 'Well, thanks anyway,' he said. He lowered his voice. 'I still have the Doctor's syringe. We'll get another chance.' His face twisted for a moment, then straightened into a friendly grin. 'You don't know what you've done for the future of humanity.'

Steam. Smells of waterweed and of wet, warm grass.

Kitig was hungry. It had been a long time since breakfast, since Narunil's flowercakes served up on the wicker plates.

He wondered where Mritig was. Perhaps he ought to check on him, the little beast often went wandering in the afternoons...

'A mirror. I always find them useful, with energy weapons about.'

The Doctor. The Doctor Doctor the Uncreator the Uncreator

'Get up, Kitig, you're still alive and we've got a visitor.'

Kitig opened his eyes, reluctantly allowing himself to remember where he was.

Africa. The volcano. The lake.

Three and a half million years back in time.

He was lying on his side in the long grass just above the beach. There was a Tractite standing over him: a Tractite in full body armour, with the glittering lights of machines in a collar around his neck. A Tractite who smelled wrong. Alien.

The scents are changing.