The ground beneath vanished for a moment, replaced by grey-blue water, streaked with golden sunlight. The alkaline lake. After a moment the water filled with flame-red bacteria, blooming where nothing else could grow.

That's us, she thought. Our colony. Blooming in the heart of the wilderness, safe from the Empire.

And, incidentally, robbing the humans of their planet. Or at least that had been the idea.

Until the Doctor came along.

The flitter's autopilot beeped, warning her that the volcano's slopes were dangerously near: she gained height quickly, following the contour of surface. Beneath her, the ground changed from pure white to a mixture of dark lava flows and small, ash-covered trees.

Then, suddenly, it was all gone, and she was flying over the vast, grey landscape of the crater. Disappointingly, there was no huge bubbling lava pool.

Still, there had to be a main vent. It was simply a matter of finding it.

She switched the flitter's display to a thermal-imaging system, and was rewarded with a rainbow of hot spots and a screaming blue-white disc that was the throat of the volcano. She locked her 'weapon' on to the disc, then let the flitter fly itself and returned the display to a natural-light view.

She watched as the bomb bay ejected its load, and the TARDIS fell in a smooth predetermined arc into the smoky darkness of the vent.

Then she swung the flitter round, and set a heading for home.

BOOK FOUR.

Mauvril looked at the Doctor's face. It was pale, and the eyes were closed, but there was a tension in the eyelids, in the muscles of the face, which told her that he was conscious. muscles of the face, which told her that he was conscious.

She had toyed with his death, testing him, watching him fail to retrieve his time machine time after time, until she was quite sure that he could not retrieve it. That it was destroyed. quite sure that he could not retrieve it. That it was destroyed.

So she had told him her story, not just because she needed to tell it, not just because he deserved to hear it, but also to keep him alive long enough for her to be satisfied. keep him alive long enough for her to be satisfied.

Now, she was satisfied. He couldn't bring back the TARDIS.

It was dead.

Soon, the Doctor would be dead too.

As soon as she'd finished her story.

'When I woke up, after killing the alien, it was dark. After a moment I realised that this was because there was a spaceship moving across the sky. Vast, sharp-edged, dark as the night sky and outlined by the stars around it. moving across the sky. Vast, sharp-edged, dark as the night sky and outlined by the stars around it.

'I'd worked out a few things while I slept. I suppose you do, even when the sleep is a preparation for death. Perhaps especially then. Anyway, I knew that this immense machine in the sky had come to destroy me, because I had destroyed one especially then. Anyway, I knew that this immense machine in the sky had come to destroy me, because I had destroyed one of its people. I'd realised that the alien I'd killed was a human, despite the body armour: I think I'd worked out that the of its people. I'd realised that the alien I'd killed was a human, despite the body armour: I think I'd worked out that the armour, like the glittering fibre optics around her eye, was a machine. And I knew that this was an invasion, that the armour, like the glittering fibre optics around her eye, was a machine. And I knew that this was an invasion, that the humans wanted to destroy us. I'd remembered the Earth Reptile's warning, and worked out what it had meant. humans wanted to destroy us. I'd remembered the Earth Reptile's warning, and worked out what it had meant.

'Poor Pakip, I thought. He should have listened to his friend.

'I was quite calm. I didn't care, you see. I knew now that the humans had decided to destroy us, as they had destroyed others before. If that was the case, then everyone every Tractite, of every land was going to die. My death, at least, others before. If that was the case, then everyone every Tractite, of every land was going to die. My death, at least, would be a deserved one. I even thought that it was possible that all of Tractis deserved to die: for surely, if the Earth would be a deserved one. I even thought that it was possible that all of Tractis deserved to die: for surely, if the Earth Empire with all its glittering power had decided we weren't fit to exist, it must be true. So I lay there, a tiny, half-dead horsy Empire with all its glittering power had decided we weren't fit to exist, it must be true. So I lay there, a tiny, half-dead horsy quadruped, and I waited for the explosion of light which would kill me and absolve me of my crime. quadruped, and I waited for the explosion of light which would kill me and absolve me of my crime.

'It didn't happen, of course. Perhaps if I'd been moving around, and anyone on the ship had noticed I was alive, they might have taken the trouble to kill me. But more probably not. They had other business. So the ship crawled overhead, an might have taken the trouble to kill me. But more probably not. They had other business. So the ship crawled overhead, an inverted landscape of dead, jagged metal, and it didn't even notice me. An hour after it was gone, I was still waiting for inverted landscape of dead, jagged metal, and it didn't even notice me. An hour after it was gone, I was still waiting for death, only half conscious, when there was a false sunrise on the northern horizon. death, only half conscious, when there was a false sunrise on the northern horizon.

'I stood up, on shaky legs, and took my bearings. There was only one city in that direction: Noctutis, the capital of our land, the city of my dreams, the city of all that spice and perfume and dancing and gold and beauty, the city I had never land, the city of my dreams, the city of all that spice and perfume and dancing and gold and beauty, the city I had never actually seen, but dreamed of so much and one day hoped to see. actually seen, but dreamed of so much and one day hoped to see.

'And now that city was dead.

'I think it was the death of my dream, rather than the deaths of the two million or so of my people living in the city, that affected me then. It made me angry. Angry enough to want to live at least, to live long enough to find out what had affected me then. It made me angry. Angry enough to want to live at least, to live long enough to find out what had happened, whether we really deserved this and, if so, why. happened, whether we really deserved this and, if so, why.

'So I took the weapon from the thing that I had killed and started to try to understand the function of the switches and levers attached to it. I don't think I was consciously planning to kill any more invaders, not as such. That was still a taboo. I levers attached to it. I don't think I was consciously planning to kill any more invaders, not as such. That was still a taboo. I was just trying to find a way to survive for a few days, at least. I think I somehow imagined I would hijack one of their flitters and get off the planet. I thought about trying to find the Earth Reptile, Menarc, and asking him to intercede with the was just trying to find a way to survive for a few days, at least. I think I somehow imagined I would hijack one of their flitters and get off the planet. I thought about trying to find the Earth Reptile, Menarc, and asking him to intercede with the Empress for us. Empress for us.

'But as the days passed, and the refugees came out from the cities, thousands of them, starving, terrified, I began to realise what the invasion really meant. It wasn't just the end of my dreams, but the end of a whole world. Our world was realise what the invasion really meant. It wasn't just the end of my dreams, but the end of a whole world. Our world was being picked apart, a whole, complex web of culture and civilisation, a worthy civilisation, was being reduced to nothing being picked apart, a whole, complex web of culture and civilisation, a worthy civilisation, was being reduced to nothing more than a few random glimmerings, like the movement of light along those fibre-optic cables in the dead human's eye. I more than a few random glimmerings, like the movement of light along those fibre-optic cables in the dead human's eye. I realised the value of the peaceful, dull, Tractite culture I had been brought up in only as it was being destroyed. I could tell realised the value of the peaceful, dull, Tractite culture I had been brought up in only as it was being destroyed. I could tell you many stories: deaths, nightmares. But this is my story, and I dare say you've heard and seen more than enough you many stories: deaths, nightmares. But this is my story, and I dare say you've heard and seen more than enough stories like that on your travels. stories like that on your travels.

'What's more important is the effect that it all had on me. Slowly, I became a killer. Killing in self-defence became killing in the defence of others, became killing in anticipation of attack, became killing for the sake of killing. I don't know killing in the defence of others, became killing in anticipation of attack, became killing for the sake of killing. I don't know when I actually started to enjoy it. When I discovered I could have blood lust, just as if I were a carnivore. When I started when I actually started to enjoy it. When I discovered I could have blood lust, just as if I were a carnivore. When I started torturing the humans, just as they had tortured us. When I started drinking their blood, for the salt, for the hatred. But I torturing the humans, just as they had tortured us. When I started drinking their blood, for the salt, for the hatred. But I know that it silted up my mind thickened it. I had nightmares in which I killed my brother, and his wife, and their child, in know that it silted up my mind thickened it. I had nightmares in which I killed my brother, and his wife, and their child, in which I pulled the trigger on a vast blaster weapon and burnt out Tafalis and Noctutis and all those people and all my which I pulled the trigger on a vast blaster weapon and burnt out Tafalis and Noctutis and all those people and all my dreams. dreams.

'I had become my enemy.

'Can you understand that?'

The Doctor's eyes opened, but he said nothing.

After a while, Mauvril went on.

'Can you understand, then, how we felt when we found the time tree? Can you understand how we realised that this strange alien plant with its orange leaves and its appetite for heavy metals could actually turn back time, and knew that we strange alien plant with its orange leaves and its appetite for heavy metals could actually turn back time, and knew that we had to do it? had to do it?

'At first we were going to sabotage the invasion but how? We would have to smuggle a six-metre tree into orbit position it exactly and make it travel back an exact number of years! No, it was too difficult. The nature of the plant made precise settings impossible. We needed a broad, easy target and I thought of it.

'I thought of it.

'You can understand it, can't you? The temptation? It would all just go away. The invasion would simply never have been. All of our terrible crimes would vanish. Our lust, our hatred, would be gone. We would never have to drink blood. We been. All of our terrible crimes would vanish. Our lust, our hatred, would be gone. We would never have to drink blood. We would be clean again. would be clean again.

'And the human race would never have existed.

'Of course it wasn't easy. Our first jump only took us back a thousand years, for some reason. One of my people was left behind in the confusion that followed, with a seedling from the tree I don't know what he did, he may have tried to continue the mission. Some of the things that Kitig has said make me think this could be the case. behind in the confusion that followed, with a seedling from the tree I don't know what he did, he may have tried to continue the mission. Some of the things that Kitig has said make me think this could be the case.

'The second jump was better. We arrived in a primitive human village. But one of the humans got into the tree, and one of my soldiers panicked and shot it. The tree jumped out of control; we ended up here. There were no humans, and astro-nomical evidence suggests we have arrived before the human race evolved. of my soldiers panicked and shot it. The tree jumped out of control; we ended up here. There were no humans, and astro-nomical evidence suggests we have arrived before the human race evolved.

'What else is there to do but survive? And, in surviving, replace our enemies?

'Doctor, do you understand what we have done? There has been no killing only one small village of humans has died and yet we have destroyed the human race. Kitig has told me the story of his people, the mystery of their origin. The fact that they are peaceful. that they are peaceful.

'Doctor, I want to believe that you will accept that what we have done what we have achieved is the best future for the universe. I want you to believe that. I want you to forgive me before you die. the universe. I want you to believe that. I want you to forgive me before you die.

'Please, Doctor.'

The Doctor stirred at last. The blue green eyes opened, turned to meet Mauvril's.

After a long while, he spoke.

'If you want me to forgive you ' A rattling breath, a silence.

'Yes?' Mauvril wondered if he would beg for mercy.

'Fetch Kitig.'

CHAPTER 19.

The place where the TARDIS had materialised was still marked by a faint depression in the short grass, and by a right-angled bite taken out of the hard soil.

'That's what's different,' Sam said over her shoulder to Jo. 'Corners.'

Jo looked down at her, squinting in the bright, low morning sunlight. 'You mean that's the difference between natural landscape and cities?'

They'd been talking about it on the way across from the gorge. Both of them needed distraction from the one big fact of their lives, the fact that the Doctor had been gone six days.

Six days.

Sam hadn't asked whether Jo had ever been abandoned by the Doctor for that long. Jo hadn't asked Sam about it, either.

Both of them avoided talking about it as far as possible.

'Yup, I think so,' she said, in reply to Jo's question. 'In cities, everything's designed. Even if it's curved, even if it's a mess, it's still got corners. Corners from up here.' Sam tapped her head. 'But all this...' She waved her arm around at the enormous landscape.

Every hummock, every ridge, every thorn tree cast a long, rough shadow in the grass. The irregular cone of the volcano seemed to be floating on a shimmering something that might be a lake, or might be an illusion. In the other direction, a low ridge of hills retreated towards the horizon, each distinct peak higher than the last, jumbled green and buff and ochre rock streaked with shadows. The first outcrops of the hill were only yards away, low, random rocks, subtly uneven.

'Not a corner in sight,' Sam concluded.

'Not everything man-made has corners. There are trees and parks.'

'Trimmed trees. Planted-out, well-watered, looked-after parks. Even if you go for a walk in the woods, they've been "managed". This hasn't been managed.' She paused. 'That was the difference with the Tractite world with Paratractis. It was still Earth, really, but it was still wild too can you understand that?'

'Maybe you just didn't recognise the alien corners.'

Sam looked up. She'd begun to realise that Jo was a good deal brighter than she seemed. With her striped sweater and floppy hat she seemed so... daffy. So English and old-fashioned.

But she knew how to survive in this environment. She was the one who had picked their campsite, she was the one who had found fresh water, she was the one who had managed to light a fire.

The fire had at least kept the habs away.

'Maybe not,' she admitted. 'But I wish there was more of this on our Earth.'

Jo squatted down, brushed the hair away from her eyes. 'You sound as if you think Jacob was doing the right thing.'

Sam looked away, swallowed. She She had pushed the plunger. had pushed the plunger. She She had infected the habilines. had infected the habilines. She She was responsible. was responsible.

Jo put a hand on her arm. 'Sorry. That was tactless.'

'No. It's OK. I... sort of thought he was, for a while. When we went to Paratractis, it was so beautiful. And what the humans had done to the Tractites in the alternative reality in our our reality was so horrible. But ' reality was so horrible. But '

She broke off. Jo's hand on her arm had tightened, and she was staring into the long grass.

A shadow.

No.

A habiline.

'Sam, I think we're in trouble.'

Sam turned, saw that the habs were standing in a ring around them. The males, and some of the females, were swinging the heavy stone axes in their hands.

Axeman stepped forward.

'Death,' he said, pointing towards the nearest hill, where the habiline settlement was. 'Death. Death.'

He pointed at Jo and Sam, each in turn.

Sam felt her stomach heave in panic.

Jo grabbed her arm. 'Run!'

Sam hesitated for a second, staring into Axeman's eyes. Was there any hope of making him understand?

'Jacob did this,' she said. 'Not us.'

Which isn't entirely true, she thought, with a sick feeling.

'Stranger,' said Axeman, pointing at them again. 'Stranger. Stranger. Enemy. Enemy. ' He raised the axe. ' He raised the axe.

Sam ran.

Jo was ahead of her, waving her arms back and forth. After a moment, Sam saw the stone axe held double handed.

Brown habiline bodies moved in front of them, dancing, screaming, teeth bared. Drool and sweat flew. Jo became aware of a rhythmic shout, almost like a football chant, a ceremony ceremony. This was a ritual killing ritual killing and then there was only rock in front of her, a bare reddish wall of rock, and they were going to be pinned against the hillside, pinned against the rock and and then there was only rock in front of her, a bare reddish wall of rock, and they were going to be pinned against the hillside, pinned against the rock and Killed The rains had come. The air on the lake shore was clear and fresh, the grass on the plain high and green and glittering with new flowers.

Kitig trotted along the narrow beach, as he did twice every day, morning and evening. Quite a lot of Mauvril's troopers did the same. He could see them, bunches of jogging figures moving clockwise around the shore, some of them casting up spray as they cut across the shallow water of seasonal streams.

Kitig jogged anticlockwise.

He'd come to enjoy dodging them, making them steer into the water or into the long, cutting grass. They cursed him, but they knew he had Mauvril's protection, and he'd received nothing worse than a few painful 'accidental' kicks.