'Now look here, Susan,' began Ian. He gave up in despair.

'Come on, Barbara, let's get out of here.'

'You can't get out,' cried Susan. 'He won't let you go!'

Ian pushed past her and strode up to the Doctor, who was still standing at the control panel. He gazed down at the maze of switches and dials.

'Susan closed the door from here, I saw her. Now, which is it, Doctor? Which control operates the door?'

'Still think it's all an illusion?' asked the Doctor mockingly.

Ian glared at him. 'I know that free movement in Time and Space is a scientific dream that isn't going to be solved in a junk yard!'

'Your arrogance is nearly as great as your ignorance, young man!'

'Will you open the door?'

The Doctor gave another of his mocking chuckles.

'Open that door!'

The Doctor didn't move.

Ian looked appealingly at Susan. 'Won't you help us, Susan?'

She hesitated, then shook her head. 'I'm sorry, I mustn't.'

Ian reached out towards the console. 'Very well, then I'll have to risk it myself.'

The Doctor shrugged. 'I can hardly stop you.'

(Only Susan saw the Doctor's hand reach out to the console and flick the immobiliser switch.)

Ian reached out to the controls and hovered for a moment.

As his hand came down, Susan screamed, 'Not that one, it's live!'

It was too late. Ian touched the faulty switch, there was a crackle of power, and he was hurled clean across the control room.

He slumped dazed against the wall, and slid to the floor.

Barbara ran to kneel beside him. She looked angrily up at the Doctor.

'What on earth do you think you're doing? Ian, are you all right?'

'I think so. Just a bit shaken.'

Barbara helped him to his feet.

Susan was talking to the Doctor in a low urgent voice.

'Grandfather, let them go now, please.'

The old man shook his head in childish obstinacy. 'By tomorrow we should be a public spectacle, a subject for news and gossip!'

'They won't say anything.'

'My dear child, of course they will! Put yourself in their place.

They're bound to make some sort of complaint to the authorities or, at the very least, talk to their friends.' He paused impressively. 'If I do let them go, Susan, we shall have to go as well.'

'No, grandfather.'

'My dear child, there's no alternative.'

'But I want to stay. Look, grandfather, they're both good people. Why won't you trust them? All you've got to do is make them promise to keep our secret.'

'It's out of the question.'

'I won't go, grandfather. I won't leave the twentieth century.'

Susan drew a deep breath. 'I'd rather leave the TARDIS - and you.'

It was clear that the old man was badly shaken by Susan's threat. 'Now you're being sentimental and childish,' he snapped.

'I mean it, grandfather!'

'Very well. But remember, if they go, you must go with them.

I'll open the door.' He went over to the console.

Relieved that the nightmare seemed to be ending at last, Barbara whispered, 'Are you coming, Susan?'

But Susan was watching the Doctor. His hands performed a complicated series of movements over the control console, and the central column began to rise and fall.

'No, grandfather,' screamed Susan. 'Mr Chesterton, stop him.

He's starting the ship. We're going to take off!'

Instinctively, Ian leaped across the control room, and grappled with the Doctor. Once again he discovered that the old man was far stronger than he looked. With a mighty effort, Ian managed to drag the Doctor away from the console. But suddenly the old man twisted in his grasp, dashed to the console and pulled what was obviously some kind of master switch. The whole control room seemed to spin like a top. Ian and Barbara were both hurled from their feet, and everything went black...

It was just as well that there was no one in the junk yard. If the policeman on the beat had paid a return visit at this particular moment, he would have seen a most extraordinary sight.

With a strange wheezing groaning sound the blue police box simply faded way.

The TARDIS was in flight.

4

The Dawn of Time

It was a bleak and rocky plain, rimmed by distant jagged mountains. A broad sluggish river ran through the centre of the plain, fringed by dense, impenetrable forest. There were caves in the foothills of the mountains, and it was here that the Tribe made their home.

In many ways they were fortunate. Once the wild beasts who laired in them had been driven out, the caves were warm and dry.

There was water from the river, fruits and berries in the forest. There was game in the forest too, savage beasts who provided meat for the stomachs of the Tribe, and skins for their clothing - if you could kill them, before they killed you.

The man called Kal was a newcomer to the Tribe, but he was by far the best of its hunters, skilled and patient and cunning. Kal never returned to the caves without the carcass of some kill, and it was this above all that had won him acceptance.

One day Kal was following tracks at the edge of the forest when he saw a miracle. There was a wheezing groaning sound, quite unlike the roar of any beast. Peering cautiously from the edge of the forest, Kal saw a strange blue shape appear from nowhere.

Many of the Tribe would have fled in terror, but Kal was more intelligent than the rest, and with the intelligence came curiosity.

Although his heart was pounding with terror, he stayed where he was, watching the blue shape to see what it would do. Kal wanted more than acceptance from his new Tribe. He wanted power - the power of the leader. He wanted Hur, the most beautiful maiden in the Tribe, to be his mate. And he wanted to kill Za, son of the old chief, his only serious rival.

Kal stared hungrily at the blue shape, tugging at his short jutting beard. Here was something new, something that so far only he had seen. His scheming mind considered the novelty, looking for ways to turn it to his own advantage... If there was magic here, he would find a way to make it work for him...

In the great central cave of the Tribe, they were waiting for magic too. Za sat cross-legged before the ashes of a long-dead fire, the Tribe gathered around him in a circle. Men and boys, women and children, all watched intently as Za plunged his hands into the ashes, gripped the charred and blackened fragments of wood until they splintered in his grasp, his face twisted with concentration, his great muscles knotted with strain, as if determined to force the dead sticks to do his will.

But the ashes remained cold and dead.

The slender dark girl by his side produced a carved rattle of bone. It was an ancient and holy object, and there was a low gasp of awe. Za shook the rattle angrily at the ashes, then plunged his hands into them yet again. Nothing happened. Za's shoulders slumped despairingly.

A little apart from the rest of the Tribe, a skeletal, grey-haired old woman sat mumbling on a bone. This was Old Mother - Za's mother - the mate of his dead father, Gor. When Gor had been alive and chief, the best of the food and skins had come to Old Mother by right. Now she was nothing. According to the custom of the Tribe, she should have been cast out of the cave to die, but some streak of softness in Za made him keep her alive. Strangely enough, this only made her despise her son the more. Za would never make a chief like his father. 'Where is the fire that Za makes?' she cackled.

The girl at Za's side was called Hur. She was quick to come to his defence. 'The fire is in his hands, Old Mother. It will not go into the wood.'