Gripping the edge of the panel, the Doctor threw all his weight against it. The panel slid a few more millimetres aside and then jammed fast.

'You cannot come in!' rapped a nasal, almost metallic voice.

The Doctor pondered a moment, trying to a.s.sess what kind of man he was going to have to deal with. 'I just want to have a word with you,' he said casually.

There was another silence.

Setting his jaw with determination, the Doctor again heaved at the shutter for all he was worth. It refused to budge, but he thought he detected a clicking noise from the other side.

'I said you cannot come in!' rasped the strange voice with menacing emphasis.

'I regret that you oblige me to resort to physical force...'

declared the Doctor distastefully. He listened again, and since there was no further reaction from within, he looked around for something to use as a crowbar. His sharp eyes lit upon a length of stout metal rod protruding from one of the smashed airlock mechanisms. Working it free, he inserted it between the edge of the panel and the bulkhead and started to try and lever the shutter open.

8.

In the angry red twilight Barbara and Ian had been exploring the awesome sprawling wreck of the Astra Nine Astra Nine.

Ian had been trying to find a way to clamber up into the escape hole cut into the bottom of the vast spherical a.s.sembly, but Barbara warned him about the radioactive contamination that Vicki had mentioned earlier. Then they had wandered down to the gigantic rear section of cl.u.s.tered cylinders and again Ian had tried to discover some way, of gaining access to the huge silent structure.

'I wonder what the ship was carrying,' Ian said, giving up and setting off towards one of the detached cylinders sticking up at an angle out of the sand.

Barbara followed him rather reluctantly, telling him what little she had gleaned from her conversation with Vicki. She watched as the intrepid science teacher pushed his way into a kind of huge funnel through layers of gauze-like metal foil.

'I think this is some sort of filtering device...' Ian called, vanishing behind the flimsy metal curtains.

A sudden noise up on the ruined terraces made Barbara look round with a startled exclamation. In one of the gaping black portals she thought she caught a glimpse of two silver figures standing motionless staring out across the pains. Then they were gone.

'What's the matter, Barbara?' Ian cried, emerging from the funnel structure.

She pointed up at the ruins. 'I saw something up there,'

she said vaguely.

'What?'

'I don't really know, Ian. They looked like two... two figures in s.p.a.cesuits... They were all silvery.'

Ian stared along the deserted terraces.

'They weren't like that Koquillion thing,' Barbara went on, taking Ian's arm and trying to pinpoint the exact spot.

Ian shrugged. 'Well, there's nothing there now.' Barbara shivered. The air had grown surprisingly chilly after the long hot day.

'Perhaps they were some of the crew,' Ian suddenly suggested. 'Maybe some of Vicki's people survived after all!'

Barbara clutched his arm uneasily. 'No. They weren't like... I don't think they were people people...' she said in a hushed voice.

'Oh come on, you're imagining things, Barbara Wright,'

Ian laughed. 'You're as bad as that awful little Tracey Pollock in 3B!'

'Tracey Pollock...' Barbara murmured. Coal Hill School suddenly seemed a million miles away. In fact it was a great deal further and long since buried beneath the Metropolitan Disposal Plant.

All at once Vicki appeared silhouetted in the hatchway in the distance. 'Barbara... Ian... Oh, there you are!' she called with evident relief. 'I was hoping you wouldn't be far away. It's not safe to venture out after dark. Please come back.'

They all went back inside.

Vicki explained that the doctor had gone to visit Bennett. Then she turned to Barbara, clearly ashamed and embarra.s.sed. 'Barbara, I am really very sorry for what I said before,' she confessed shyly. 'Please forgive me.'

Barbara smiled. ' You You must forgive must forgive me me, Vicki. I'm very sorry too.'

Vicki nodded. 'Of course you could not have known about Sandy. I over-reacted... I suppose I have grown used to being on my own recently...'

'But you're not alone...' Barbara began.

'Of course you're not,' Ian put in eagerly. 'What about this Bennett or whatever his name is?'

Vicki pulled a face. 'Bennett and I do not get on,' she admitted.

Ian grinned sympathetically. 'I know what you mean.

We felt the same way at first with the Doctor.'

There was a pause. Vicki studied them with renewed interest. 'You must be from Earth too,' she said eventually.

They both nodded.

'How long have you been away?'

Ian and Barbara exchanged wry smiles.

'Well, we originally left Earth in 1963,' Barbara replied.

Vicki's mouth dropped open in amazement. 'That means you should both be about... about five hundred and fifty years old!' she exclaimed incredulously.

' What! What! ' Barbara and Ian chorused. ' Barbara and Ian chorused.

'Father and I left Earth eight years ago,' Vicki told them. 'In 2493.'

Barbara did a rapid bit of metal arithmetic and a look of mock horror crossed her face. 'Then that makes me about five hundred and fifty five!' she giggled.

Ian nudged her. 'Well, Miss Wright, you certainly don't look your age!' he confided gallantly.

Barbara wrinkled her nose at him. 'I try not to think about it too often,' she admitted with a chuckle.

Ian winked at Vicki. 'Actually, our ship is rather on the slow side,' he joked.

Vicki stared at them in utter bewilderment. 'Stop being so silly,' she eventually protested. 'You would have to be pure time-travellers - not just relativistic ones!'

'We are are pure time-travellers,' Ian retorted in mock seriousness. 'The Doctor's TARDIS travels through the s.p.a.ce-Time Continuum.' pure time-travellers,' Ian retorted in mock seriousness. 'The Doctor's TARDIS travels through the s.p.a.ce-Time Continuum.'

Vicki screwed up her face and then shook her head in disbelief. 'That's impossible!' she laughed. 'Scientists gave up that dream two centuries ago. They certainly couldn't do such an incredible thing in 1963. They knew nothing nothing then!' then!'

Barbara's hackles rose and she stood up preparing to defend her civilisation.

What's so special about this old crate then?' Ian demanded, stamping hard on the floor of the hull.

Vicki looked nonplussed. 'Old crate?' she echoed, puzzling over the unfamiliar expression. Then she understood. ' Astra Nine Astra Nine is capable of travelling at approximately half the speed of light,' she informed them proudly. 'In our eight year journey we have covered more than thirty-seven trillion, five hundred and forty billion, five hundred million kilometres.' is capable of travelling at approximately half the speed of light,' she informed them proudly. 'In our eight year journey we have covered more than thirty-seven trillion, five hundred and forty billion, five hundred million kilometres.'

Ian shrugged. 'The Doctor's TARDIS can do that in no time at all,' he boasted. 'He visited our time on Earth and kidnapped us.'

'The Doctor is from a different planet, a different age, a different universe altogether,' Barbara explained impressively.

Vicki glanced at the internal hatch through which the Doctor had gone to visit Bennett. 'That eccentric old man?' she said sceptically. 'Then where does he come from? And when? And why?'

'And who who?' Ian muttered wryly, exchanging a helpless glance with Barbara. He shrugged and laughed. 'You know, Barbara, it's amazing how long we've been with the Doctor and yet we know as little about him now as we did when we first met him!'

Barbara gave him a pale smile. Her headache had come back again and all this argument was making her feel faint and exhausted.

Vicki stared at the two strangers, unsure whether she was being sent up or whether they were really attempting to deceive her.

'You're playing games with me,' she eventually accused them. 'I don't believe you at all. The Doctor a time-traveller? It's too silly for words. I don't believe he's even a doctor. He took hardly any notice of Barbara's injuries, you know.'

Meanwhile the subject of all this heated discussion had just succeeded in prising open the jammed shutter far enough to squeeze into Bennett's quarters. The Doctor threw down the metal rod, squared his shoulders and with head proudly erect, strode into the compartment.

To his astonishment it was empty. Bennett was not there. Momentarily disconcerted, the Doctor briefly examined the densely packed complex of equipment which took up most of the cramped compartment's surfaces. By the feeble fluorescent lighting, he searched for a second exit. But there was none. The only means of access was the hatchway through which he had just entered. Yet he had heard a voice ordering him not to come in, so how had Bennett given him the slip? The Doctor studied the edge of the hatchway and found what he was looking for.

'Now, what have we here, I wonder?' he muttered, following a pair of wires crudely fixed around the hatch frame and leading to a locker set into the hull wall nearby.

He slid open the panel and threw back his head, his bright eyes staring down his beaklike nose at the laser disc recorder and circuitry crammed into the tiny s.p.a.ce.

Delving into his pockets, he took out a short piece of wire.

'This will do for the shutter in the closed position,' he muttered. Moving to the hatchway, he connected the wire across the two crude terminals embedded in the frame at the ends of the wires leading to the recorder mechanism.

Then he returned to the locker and pressed a series of b.u.t.tons. 'Recorder primed and ready for playback...' he said with a mischievous grin. Then he went back to the shutter and took the short piece of wire connecting the terminals between his thumb and forefinger. 'Knock knock, who's there?' he chuckled, tugging the wire and breaking the circuit. 'And open Sesame...'

There was a sharp click from the locker. 'You cannot come in!' rasped the metallic voice the Doctor had heard earlier. It issued from a small speaker inside the locker.

Smiling to himself, the Doctor waited patiently for several seconds. 'I said you cannot come in!' the voice repeated, just as it had done before.

'Crude but most ingenious,' the Doctor remarked, returning to the locker and pressing some different b.u.t.tons.

The tiny speaker hissed slightly and then the Doctor heard Vicki's voice: ' ... of course I like the Doctor, ... of course I like the Doctor, ' she was saying. ' ' she was saying. ' He has such a kind face, stern but gentle too. You can He has such a kind face, stern but gentle too. You can sense that he is extremely clever. sense that he is extremely clever. ' '

' I can see that you're quite taken with the Doctor! I can see that you're quite taken with the Doctor! ' Ian's voice put in. ' Ian's voice put in.

' Strange, but as soon as he walked in here I knew that I could Strange, but as soon as he walked in here I knew that I could trust him, trust him, ' Vicki went on. ' ' Vicki went on. ' But tell me, why does he wear such But tell me, why does he wear such peculiar clothes and that long white hair? peculiar clothes and that long white hair? ' '

The Doctor frowned and c.o.c.ked his head to hear better.

' We told you, he's from another universe, We told you, he's from another universe, ' Barbara's voice said rather indistinctly in the background. ' Barbara's voice said rather indistinctly in the background.

' Please don't start all that nonsense again! Please don't start all that nonsense again! ' Vicki protested. ' Vicki protested.

' The Doctor's a genius, The Doctor's a genius, ' Ian b.u.t.ted in again. ' ' Ian b.u.t.ted in again. ' He can solve He can solve any problem... well, almost any problem you care to pose, and any problem... well, almost any problem you care to pose, and he's defeated all kinds of terrible monstrosities... he's defeated all kinds of terrible monstrosities... ' '

The Doctor switched off the apparatus and shook his head. 'Silly children, silly children,' he chuckled, obviously very touched and flattered. He stroked his chin thoughtfully. 'Intercom systems... disc recorders...

microphones... How to be in even when you are out,' he mused, turning his attention to the cluttered surfaces of the compartment, his keen eyes darting everywhere in search of something. 'Now, how do you leave the house without using the front door?'

Suddenly he noticed a small square panel under the end of the makeshift bunk. 'Aha!' he cried, kneeling down to examine it. 'Now, a.s.suming that this was originally a wall...' He pressed one of the coloured circles printed on the panel. There was a pause and then a hesitant buzzing and sc.r.a.ping sound behind him. He turned and saw a large section of the hull opening almost under him. 'Unless I am very much mistaken, this is the elusive Mr Bennett's back back door!' He peered into the dark airlock chamber and shied away as a momentary breeze of trapped hot air wafted into his face. 'Curiouser and curiouser,' he murmured, sniffing the air like a bloodhound picking up a scent. 'And the temptation is quite irresistible!' door!' He peered into the dark airlock chamber and shied away as a momentary breeze of trapped hot air wafted into his face. 'Curiouser and curiouser,' he murmured, sniffing the air like a bloodhound picking up a scent. 'And the temptation is quite irresistible!'

Vicki was in the middle of explaining to Barbara and Ian how she came to be marooned on Dido with only Bennett for company.

'After my mother died my father was offered a place on the Astra Nine Astra Nine project. I did not want to leave Earth at first,' she recalled wistfully, her face unbearably sad. 'But the Greenhouse Effect...' project. I did not want to leave Earth at first,' she recalled wistfully, her face unbearably sad. 'But the Greenhouse Effect...'

'What's that?' Ian asked, eager to gather any information that would be useful to him as science teacher at Coal Hill School that is, if he ever returned there.

'Because of the increase in the carbon dioxide content of Earth's atmosphere, the average world temperature rose and there was a danger that the polar ice would melt...'

Vicki explained.

'Causing catastrophic floods,' Ian murmured, nodding thoughtfully.

'So in the end Father persuaded me to go with him,'