The bones were charred, often ending in sharp spikes of charcoal, the ends broken away by scavengers. But they were recognisable: the femurs and ribs and skulls of apelike bipeds.

Humans.

Follow the scent of the humans.

He saw the burnt-out husk of a tree in the middle of the bonefield, and guessed what had happened.

The human village. A fire, or a weapon discharged accidentally, perhaps when one of the humans tried to get away. The time tree jolted into action by damage, sending humans and Tractites into the deep past.

Humans and Tractites.

But only the Tractites had survived.

Not because they were better, Kitig realised. But because they had the guns, and the ruthlessness necessary to kill the defenceless bipeds.

Kitig knelt down in the long grass among the bones, and thought about that. After a while, he could no longer think: he could only feel.

Feel what the humans had felt.

Terror. Anger. Madness.

He took the nearest, sharpest, spike of bone in his hand, closed his three fingers over it until the pain stopped him.

He watched the blood flowing for a while.

I will never go home, he decided. Home is built on these bones. These deaths. These burnings. It should never have existed, and neither should I.

Then, very slowly, he began to walk back to the settlement.

He had a duty to follow, and at last that duty was clear.

Sam felt rather than saw the man-ape rising out of the grass. She felt the threat, heard the roar, and was running, dragging Jo with her until the older woman too became aware of it, a rust-red demon rising from the grass with a knife in its hand A knife in its hand And it wasn't a man-ape, it wasn't Homo habilis Homo habilis or or australopithecus australopithecus, it was Homo sapiens Homo sapiens, it was Jacob Jacob, Jacob, running at them with the knife, screaming like an animal, and they were running again across the dry grass, and Jo must have realised because she was yelling 'Jacob! Jacob! Stop this!'

But Sam knew there was no chance he would stop. He was the predator now and they were the prey and Jo screamed.

Jo was falling, sinking into no over over the cliff and Sam was stopping, digging her heels and her hands into the ground and tumbling and she could hear Jo calling from below, shouting with pain, and the animal Jacob was standing over her with the knife and Jo was still screaming and Sam was fighting, a rabbit punch towards Jacob's crotch, but he'd dodged it, dodged back and the knife was coming down the cliff and Sam was stopping, digging her heels and her hands into the ground and tumbling and she could hear Jo calling from below, shouting with pain, and the animal Jacob was standing over her with the knife and Jo was still screaming and Sam was fighting, a rabbit punch towards Jacob's crotch, but he'd dodged it, dodged back and the knife was coming down

CHAPTER 20.

Sam stared at the blood pooling on the grass for a full minute before she realised that it wasn't hers.

Jacob was lying there, his body twitching.

Axeman stood over him.

The habiline was staring at the body with an expression that Sam took a moment to recognise.

Horror. Regret.

She made herself sit up, made her mouth work. 'It's OK. You had to do it.'

Axeman touched the body, shuddered.

Sam realised that Jacob's eyes were open, frosted windows staring at nothing. Her hand shaking, she reached down, awkwardly tried to close them.

It didn't work. They stayed open.

A cuff. Axeman had hit her.

She looked at him. 'Dead. Don't touch.'

Sam nodded, stood up, saw the blood splashed on her battered clothes. The air smelled of it.

Axeman pointed at himself. 'Dead.'

Sam shook her head. 'You're not dead! You oh.'

He had a fever, perhaps. One of the symptoms of the virus. He had come after her, hoping for something a cure? And he had found Jacob, and 'Thank you for saving my life,' she said.

Axeman said nothing, just pointed into the ravine.

Sam frowned.

And then she remembered, and peered over the edge, and shouted.

'Jo! Jo!'

There was no reply.

Jo ran, cursing the thickets and creepers that crowded around the muddy remains of what was probably a major river in the rainy season. She'd tried walking on the river bed, but the mud that had cushioned her fall and probably saved her life had clung on to her bruised and aching legs, refusing to let her make any progress.

Yet she had to get back somehow, she had to get back up to Sam before Jacob Try not to think about that. Probably too late anyway.

Ahead, a tree. A scrambling, deep-rooted, many-branched snake of a tree. Jo didn't recognise the species perhaps it was extinct in the modern world but it should be possible to climb.

She tried to follow the maze of branches, to plot out a route that would take her to the top of the cliff.

Then she saw something impossible.

At first she thought it was carved into the tree, perhaps by Jacob; then she realised that it was in the rock behind the tree.

Letters. Words. Words. Each one must be six feet high. Each one must be six feet high.

SAM THETA The rest was hidden.

No. Not hidden. Lost. Lost. Cut off by a dark spur of rock. A basaltic intrusion: millennia-old magma, breaking open the fossil. Cut off by a dark spur of rock. A basaltic intrusion: millennia-old magma, breaking open the fossil.

Fossil. Fossilised words.

I must have hit my head when I fell, thought Jo. I simply have to be seeing things.

A voice.

Faint, echoing, but unmistakably female.

Sam's voice.

Jo shouted back, but kept staring at the fossil. Somewhere behind her, there was a splash, a curse, and a habiline grunt.

Jo frowned, turned, saw Sam and Axeman up to their knees in one of the muddy pools.

She started to smile, then saw the blood.

'Sam are you '

'I'm fine.' The younger woman was staring beyond Jo.

At the rock wall. At the words. Her name. SAM.

'Uhh I think somebody wanted to leave a message for you,' said Jo.

Their eyes met, and they both started to laugh. Axeman looked at them in amazement.

As soon as Mauvril saw the blood on Kitig's hands, she knew. She had watched him come down from the hilltop, had watched the way he was walking, the way his head hung as if it had become too heavy, and she had suspected.

But the blood told her for certain.

'You found them,' she said.

Kitig looked up, stopped his slow, funereal walk a few yards from Mauvril. His night eyes flickered: even in the tropical daylight, she could glimpse the anger there.

Mauvril faced those eyes. 'We could have hidden them better, I suppose.'

Kitig pushed past her. Mauvril could smell the anger now, the fear and the despair.

'You knew we'd killed humans. I told you. You knew why.'

There was no reply. Mauvril turned and followed him down the paved road towards the command dome. Their hooves clicked on the coloured stone. She felt it slipping away from her: the future, the innocence and beauty she had tried to create from the fire.

'Kitig!'

He was at the door of the dome now, trying to get past the guards. They looked up at Mauvril, uncertain.

'Let him through!' she ordered. She increased her speed to a trot, caught up with Kitig in the entrance hall with its curtained-over pictures of death.

He was drawing back the curtains.

When he shouted at her, the sound was so loud that it echoed.

' This This is your civilisation!' he roared. 'This is what you tried to hide from me!' is your civilisation!' he roared. 'This is what you tried to hide from me!'

'I didn't try '

Kitig ripped back another curtain. The city glowed, Tractites died.

'You hid it from our whole civilisation. You have made it unreal.'

Another curtain. Blood, death, misery.

'You can't blame me for ' She heard the guards trotting up, waved them back.

'The Book of Keeping Book of Keeping. The Watchers. You're already doing it, aren't you? You're already writing the lies. "Just one threat. There's only one evil, one person who brings it. Everything else is dealt with by sweet reason."'

'You're not making sense. Would you rather have been fighting endless wars? Like all the other races, the Zygons and the Daleks and the Draconians and the Chelonians and the humans is that what you want now? This way, we've got a head start on everybody else in this sector practically every other species in the galaxy is still learning how to make fire. We can make all that space ours, and live in peace. For ever.' She curled the long fingers of her hands. 'Kitig, you've lived in that world. You are are that world. Surely you understand?' that world. Surely you understand?'

Kitig tore back the last curtain, stared at the images of death for a while. 'My world is based on a lie.' His voice was quieter.

'A small lie.'

'And death.'

'A few deaths.'

Kitig turned his head, and their eyes met.

'Let the Doctor go,' he said.

Mauvril closed her eyes. 'I can't,' she moaned. 'You know I can't.'

'Then I will leave your community. I will not live among murderers.' He walked past her, his body almost touching hers in the narrow passageway between the bas-reliefs of death.

Mauvril stopped him with a touch of her hand on the bare skin of his flank.

'You're my future. The future I want to build. Please don't leave me.' Her voice choked on the last word, became an inco-herent sound, a child's terror at being left alone.

She felt him trembling. 'I'm sorry.'