'TARDIS? I don't understand you, Susan.'
'Well, I made the name up, actually. TARDIS, from the initials. Time and Relative Dimension in Space. Don't you understand? The dimensions inside are different from those outside.'
Ian drew a deep breath. 'Just let me get this straight. A thing that looks like a police box standing in a junk yard... and it can travel in Time and Space?'
'Yes,' said Susan.
'Quite so,' confirmed the Doctor briskly.
'But that's ridiculous!'
Susan looked in anguish at the old man. 'Why won't they believe us?'
'Well, how can we?' said Barbara patiently. 'It's so obviously impossible.'
Susan stamped her foot in frustration, and the Doctor chuckled.
'Now, don't get exasperated, Susan. Remember the Red Indian when he saw his first steam train - his savage mind probably thought it was an illusion too!'
'You're treating us like savages,' said Ian bitterly. 'Savages or children!'
The Doctor gave his infuriatingly superior smile. 'Am I? The children of my civilisation would be insulted!'
'Your civilisation?'
'Yes, my civilisation. I tolerate this century, but I don't enjoy it. Have you ever thought what it's like to be wanderers in the fourth dimension, young man? Have you? To be exiles! Susan and I are cut off from our own civilisation, without friends or protection, but one day we shall go back.' He stared into the distance. 'Yes, one day... one day...'
Perhaps the human mind can only take in so many surprises at a time. At this new revelation, Barbara and Ian exchanged looks of sheer disbelief.
'It's true,' cried Susan desperately. 'It's all true! You don't know what you've done, coming here.' She turned to the Doctor. 'Grandfather, let them go now, please, they can't harm us. I know these people, their minds reject things they don't understand. They won't tell anyone and even if they did, they wouldn't be believed.'
The Doctor's face was suddenly cold and hard. 'No.'
'You can't keep us here!' said Ian defiantly.
'Can't I?' said the Doctor. Something about his confident smile made Ian feel very uneasy.
Barbara went over to Susan and put an arm around her shoulders. 'Susan, listen to me. Can't you see that all this is an illusion, a fantasy? If you like, it's a game that you and your grandfather are playing. You can't expect us to believe it as well.'
'But it's not a game,' said Susan desperately. 'It's not! I love England in the twentieth century. I love your school. The last five months have been the happiest of my life.'
'You talk as if you weren't one of us,' said Barbara. 'But you are! You look like us, you sound like us...'
Susan's face was solemn. 'I was born in another time, another world.'
'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.