Barbara first suspected she was lost when she became aware that the corridor in which she was walking seemed to be sloping downwards-and wasn't the rest room on a slightly higher level than the sleeping quarters? She stopped and looked about her in the half-light.

She had come to a dead end. Behind her wound the corridor she had travelled down; to her sides were two roundelled walls, in one of which there was a door. Deciding that she couldn't get any more lost than she was already she hesitated for a second, and then opened the door.

The door opened out onto a vast laboratory, almost the size of a school a.s.sembly hall. Lines of long wooden benches were covered with the most amazing variety of scientific tools Barbara had ever seen in her life. Everything from old Chinese abacuses to futuristic items of equipment, the purposes of which Barbara couldn't even guess, seemed to be here.

One entire wall was lined with computers, all of which should have been chattering busily away to each other, but which, like everything else in the TARDIS, were now deathly silent. Another wall was covered with complicated charts and diagrams.

Barbara gave a silent whistle of appreciation; even she, as unscientific as they came, couldn't help but be in awe of the size and comprehensiveness of the Doctor's laboratory.

She gave herself a little pat on the back when she saw the huge shelves on the far wall, packed to overflowing with files, papers and books. She might not have found the rest room, but surely here she would find something to take her mind off her current situation?

But when she reached the bookcase she was sorely disappointed. Book after book was merely another dry scientific treatise. Barbara looked despairingly at what to her was merely mumbo-jumbo, much of it written in strange languages and multisyllabic words she didn't know, or unearthly scripts she couldn't decipher. Sighing, she replaced a book and turned to go.

It was then that she noticed the door which, hidden in the shadows cast from the bookcase, she hadn't seen before. It seemed to be made of some heavy metal and was opened by a rotating circular handle. Curiosity got the better of the schoolteacher and she reached out to open it.

And then her heart missed a beat as a short sharp noise echoed throughout the laboratory. Turning around fearfully, she whispered, 'Who's there?'

No reply.

Barbara looked around and then breathed a sigh of relief as she saw the book on the floor. Obviously she had not replaced all the books carefully enough, and one had dropped to the floor.

Smiling, and chiding herself for her jumpiness, Barbara bent down to pick up the book. But then another book fell off the shelf. And then another. And another. And another-until every single book on the shelf was seemingly throwing itself through the air at Barbara.

Box files fell off the shelves and sprang open, sending their contents swirling and scattering in all directions, as though caught up in some eerie, intangible wind.

Barbara looked on in terror as a whole rack of test tubes swept off a nearby workbench and fell to the floor, smashing into a thousand pieces, their contents giving off noxious fumes.

Other vials and gla.s.s tubes rattled madly away in their containers. By her side a chair upended itself and crashed to the floor. Charts fell off the walls, and the floor began to shudder sickeningly beneath her.

'Who's there?' she cried. 'Why don't you just leave me alone!'

But still the nightmarish visitation continued. Finally Barbara snapped and, terrified, ran out of the room-straight into Susan.

Barbara sobbed with relief when she saw her. 'What is it?' the girl asked.

'In there,' said Barbara, nodding back towards the laboratory. 'There's something in there, throwing about all the books, equipment, everything...'

Susan looked warily into the room. The devastation was apparent but nothing was moving there now. 'It's quiet now,' she said, and then asked suspiciously: 'But what were you doing in Grandfather's laboratory?'

'I wanted to get a book,' explained Barbara, gasping for breath. 'But I couldn't find one; so I decided to explore the other rooms in the lab.'

'Other rooms?' asked Susan urgently. 'What other rooms?'

'Why, the one behind that door,' Barbara said and pointed to the heavy door in the shadows of the bookcase.

Even in the gloom, Barbara could see Susan's face turn chalky white. 'That door... do you know what's behind that door?' she asked. Barbara shook her head, and Susan continued. 'Some of Grandfather's experiments require vast amounts of power and radiation-the isotopes are stored behind that lead-screened door. If you'd've gone in there without a protective suit you wouldn't have survived for more than thirty seconds...'

'And I was about to open that door,' said Barbara slowly, 'when the attack happened.' She shook her head. 'I don't know what it was, but whatever it was it just saved my life...'

'You mean, you really do think that some sort of intelligence has come aboard the TARDIS?'

'Yes, Susan,' said Barbara. 'Don't you feel it too, that feeling that we're being watched all the time?'

Susan shivered. 'Don't let's talk about things like that now,' she urged. 'Let's get back to Grandfather and Ian.'

In the control chamber the Doctor switched on the scanner screen and played back the sequence of images which, like everything else displayed on the screen, had been automatically recorded in the TARDIS's memory banks. Once again the familiar pattern of the Malvern Hills , the planet Quinnius, and the exploding star system was being repeated. This time, however, the exit doors did not open.

He searched his mind, looking for an explanation, but found he could not make head or tail of it. Defeated, he shook his head and deactivated the scanner.

He wandered around the central console to another of its six control panels, the one which included the mechanism which would open the TARDIS's great double doors onto the outside world. For a moment he considered the wisdom of the action he was going to take. Then, flexing his fingers, he lowered one ringed and bony hand down to open the doors.

Before he could reach and operate the control he felt two strong hands close tightly around his neck, dragging him back, attempting to throttle him. In desperation the Doctor struggled to shrug off the attack and then managed to turn around to confront his unknown a.s.sailant.

8

Accusations

It was Ian. Wild-eyed and obsessed, he grabbed viciously at the Doctor's throat. Amazingly the frail old man was able to push the younger man away and, still suffering from the effects of the Doctor's drug, Ian fell crashing to the floor.

Ma.s.saging his throat, the Doctor staggered over to a chair as Barbara and Susan burst into the room. Barbara took in first the figure of Ian falling senseless to the floor, and then the Doctor, stunned and gasping for breath on a chair.

She rushed over to Ian's side. Susan ran to her grandfather.

'It's no use pretending now!' crowed the Doctor as he got his breath back. 'I was right! It was you all along!'

'Don't just sit there!' cried Barbara, not listening. 'Come over here and help him!'

'Help him?' spluttered the Doctor. 'You saw what he tried to do! He nearly strangled me!'

'I saw nothing!' Barbara snapped back. 'All I can see is that he's fainted... just like Susan...'

'Susan didn't faint,' retorted the Doctor angrily. 'It was you who told her she did-and I very nearly believed you!'

'What does it matter?'

The Doctor, not as hurt as he would have liked to have made out but merely shaken, stood up with the help of a confused Susan.

'Matter, young lady, matter?' he said with affronted dignity. 'That barbarian down there very nearly strangled me! He's no better than those cavemen we met!'

Barbara was no longer paying any attention to the Doctor's self-righteous prattling. 'But he has fainted,' she repeated. 'Look at him.'

'Oh, he's merely play-acting,' dismissed the Doctor, without bothering to look down at the unconscious schoolteacher.

Barbara looked up seriously, her face set in firm concern. 'Doctor, he has has fainted and I can't believe he wanted to kill you. Don't you see that something terrible's happening to all of us?' fainted and I can't believe he wanted to kill you. Don't you see that something terrible's happening to all of us?'

'Not to me,' countered the Doctor, 'nothing at all has happened to me.'

You stupid old man, can't you see that you're the worst affected of the lot of us! thought Barbara viciously. Lower your idiotic defences for just one minute and see what's happening to us!

'This is undoubtedly a plot between the two of you to get control of my Ship,' the Doctor a.s.serted.

'That isn't true!'

'Can't you see I've found you out?' chuckled the Doctor, highly satisfied with his deductive skills. 'Why don't you just admit it?'

'No, why don't you admit it?' countered Barbara savagely. 'Why don't you admit that you haven't a clue as to what's going on around here, and so to save your own precious self-esteem, you're clutching at straws, shifting the blame onto everyone and everything apart from your own precious self!'

She laughed self-deprecatingly. 'Get control of the Ship! We wouldn't know what to do with it even if we had. If you can't operate your own machine I see absolutely no chance of Ian and myself ever working it!'

The Doctor's face reddened with fury at having his ability to control the TARDIS brought into question once more.

'How dare you!' he exploded. 'I will not tolerate this any longer. I told you I'd treat you as my enemies-'

Susan who had remained quiet up to now, scarcely understanding what had been going on and torn between two conflicting loyalties now spoke up. 'No, Grandfather,' she pleaded.

Slightly taken aback, the Doctor looked down at his granddaughter.

'There is no other way, Susan,' he said imperiously.

'But...'

'There is no other way, my child,' insisted the Doctor sternly.

Susan bowed her head in defeat, recognising her grandfather's firmness of purpose.

Down by Barbara's side on the floor Ian was beginning to stir but Barbara continued to look up at the Doctor. 'What are you going to do?' she asked apprehensively.

'That, madam, is my concern.'

Barbara turned back to Ian and shook him. 'Come on, Ian, wake up! For heaven's sake, help me!'

Ian muttered a few indistinct words, and Barbara strained to hear them.

'There is no alternative,' continued the Doctor superiorly. 'Your little antics have endangered all our lives.'

Susan crossed slowly over to Ian and Barbara. She had entered the control room a little after Barbara and had not seen as much as the schoolteacher.

'How did he get like this?' she asked, looking down at Ian.

'It's all a charade,' insisted the Doctor flatly.

Susan repeated her question.

'He went near the control panel...' Barbara said slowly, and suddenly realisation dawned. 'Just like...'

'Just like me,' finished Susan and looked back to the Doctor. 'Grandfather, it did happen to me,' she said earnestly.

'That's right-you remember now!' interrupted Barbara, delightedly seizing on Susan's words. 'You lost your memory and there was this terrible pain at the back of your neck.'

'Yes, that's true...'

'What did you think we'd done?' asked Barbara, 'Hypnotised you? Drugged you? Susan, believe me, we wouldn't do anything like that to you!'

'Wouldn't you now?' asked the Doctor cynically. 'I begin to wonder just what it is you and that young man are not capable of. You break your way into my Ship, sabotage its controls and now you are attempting to divide and conquer. She's trying to poison your mind against me, Susan-'

Just then, Ian tried to sit up, and reached out a hand towards the Doctor.

'Doctor... the console... stay away... the controls are alive...' he croaked.

Barbara flashed the Doctor a venomous look. 'You see? He wasn't trying to kill you after all! He was trying to pull you away from the control panel. Don't you see? He wasn't trying to harm you, he was trying to help you-though Heaven knows why!'

For a moment the Doctor appeared shaken, as if the truth of Barbara's arguments was just beginning to filter into his mind. Then Susan went over to him and took his arm gently.

'Grandfather, I do believe them,' she said softly. 'They wouldn't have done all those terrible things you said they would.'

But even his granddaughter's words wouldn't sway the Doctor from his irrational and stubborn belief.

'Whose side are you on, Susan?' he asked coldly. 'Mine or theirs?'

'Can't I be on both?'

The Doctor shook his head. 'Oh, I admit they have been very smart,' he said, but this time his voice didn't quite carry the amount of conviction it had previously.

'No, its not a question of being smart,' countered Susan firmly.

The Doctor took his granddaughter protectively in his arms. 'Don't you see I won't allow them to hurt you, my child? These humans are very resourceful and cunning-who knows what other schemes they may have devised to harm you? You must realise that I am left with only one recourse. They must be put off my Ship!'

Susan broke away from the Doctor's embrace. 'No, Grandfather, you can't!'

'I can and I must.' The old man's tone was final.

'But you can't open the doors,' protested Barbara. 'The controls are dead!'

'Don't underestimate my powers, young lady!' riposted the Doctor.

'But, Grandfather, you've no way of telling what's out there now that the scanner isn't working properly,' protested Susan. 'There may be no air; it may be freezing; it might even be too hot to exist...'