Meanwhile a.s.sign this creature an identification disc and put her to work apt.i.tude level three.'

'Work? What do you mean?' Sarah protested.

'As a member of an inferior race you either work to serve the cause of Averon, or you die,' Baal said with brutal simplicity. 'For example: Guard 16 direct integral projector at subject's head. Prepare to fire a maximum energy burst.'

To Sarah's horror the left arm of the nearest robot lifted obediently to point between her eyes. She realized its arms were differentiated: the right had a large five-fingered hand similar to Baal's, but the left ended in a heavy double-flattened claw like the jaws of a vice, which opened wide to allow a thick transparent rod to emerge. She gasped in fear, twisted her head aside and pulled futilely at her bonds. The robot's right hand caught hold of her chin to hold her still and brought the gun muzzle up to her forehead.

'I'll work, I'll work!' she choked out.

'That is wise,' Baal said. 'Put the identifier on her.'

The other robot had gathered something from a part of the chamber Sarah could not see. Now it was held up before her eyes. It was an oval plate of blue metal perhaps three inches across and two wide, slightly curved, with the boldly embossed number 1073 picked out on it in red. The robot reversed the plate. Two short pins projected from its other face. Before Sarah realized what was intended the plate was pressed hard against her forehead. She yelped in pain as the pins stabbed through her flesh and into the bone beneath. Then there was just a surprising cold numbness. The bands that had restrained her snapped open. She dropped to her knees, sickened, trying to draw her stiff and aching arms up so that she could tear at the plate.

'Any attempt to remove the identifier by force will automatically release a lethal electric discharge,' Baal warned.

Sarah very slowly lowered her hands. 'It also incorporates a locator, and will be triggered remotely if you cross a forbidden perimeter or fail in your work. There is no escape. Take her away.'

The image of Baal faded from the screen. One of the robots caught Sarah under her arm and lifted her effortlessly to her feet. She staggered along in its metallic grasp as it led her through a door and down a long corridor. A second heavier door slid open and she blinked in the sudden sunlight as they emerged from one of the domes at the centre of the complex she had observed from the heights earlier, with the mast now rising high over her head.

As the robot took her through a gate in the fence that separated the domes from the rest of the compound, Sarah tried to pull herself together. It was not the easiest of mental exercises to undertake, since she felt about as despondent and hopeless at the present moment as she could ever remember.

Steeling herself she cautiously touched the plate on her forehead with her free hand. It didn't hurt at all, but she was acutely aware of its presence, and she felt sick again. Just what sort of a hole she had got herself into, and where were the Doctor and Harry?

Once through the gate the robot led her past the nearest of the long low factory-like buildings and she heard the whirr and buzz of machinery. From ground level she now saw it had several large open doorways, through which figures were visible working purposefully at some sort of production line.

The workers seemed to be of several different species, but they had one thing in common: as far as she could tell they all wore identifier plates. Her feet began to drag again dejectedly at the sight. As the robot's pace was a little faster than she could comfortably walk, she began to feel as though her arm was going to be pulled off at the socket. Indignation and defiance welled up within her and she burst out, 'Oi, slow down I won't be any good to you if I can't use my arm!'

She winced even as she spoke, instantly regretting her words and expecting some sort of punishment for her outburst.

But to her surprise and relief the robot modified its pace and eased its grip slightly.

'Thanks,' she said automatically. She tried to examine the impa.s.sive machine objectively as it clumped along at her side, its powerful form looming head and shoulders over her. Its outer body sh.e.l.l, she now saw, was patterned with scales of different sizes, even around its plate-reinforced joints, giving the impression that it had actually grown in place. Was this further mimicry of its masters, or the result of some unusual manufacturing process? Clearly it was more than an animated suit of armour and must be quite sophisticated mentally to respond as it had. Probably it was just doing its job as it had been programmed to, she rationalized. It might kill her without compunction if ordered, but it wouldn't be needlessly cruel; that was a human, and apparently alien, failing. She phrased a question carefully: 'Just so I can perform my work more efficiently, can you tell me what I'm going to be doing?'

'Basic manual labour,' the machine responded in its clear but toneless voice. 'Unpacking and distribution of new components to required locations in a.s.sembly building.'

'And, in the interests of efficiency again, what is it you actually a.s.semble here?'

The robot was surprisingly forthcoming, but of course there was hardly any point in keeping it secret in the circ.u.mstances.

'Synthonic weapons systems. Mobile autonomous devices of various types and functions.'

'You mean like you?'

'That is correct.'

Sarah decided to chance her luck. 'Has anybody ever escaped from here?'

The robot's reply was unexpected. 'All new workers ask this. Instructions require we indicate that spot.'

It stopped and pointed with one of its ma.s.sive arms to a low hillock just beyond the outer perimeter, studded with many low mounds of earth and a variety of stakes and short posts, some with crosspieces. It was a graveyard.

7.

Guided Tour hope your quarters are comfortable, Doctor,' Cara Tarron said, as 'I they seated themselves in the travel tube capsule.

The door hissed shut and the capsule moved smoothly and silently away from the residential station in the main complex, dived into a tunnel and began to pick up speed. Through a transparent wall on their right they could see out over the Valley, along the side of which they were travelling.

The Doctor beamed at her. His mood, much improved since yesterday's meeting in the conference room, was now charming, indulgent and full of bonhomie. 'Well, Academ Tarron...ah, may I call you Cara, as we're going to be working together?'

Cara felt an unexpected glow of pleasure at his request.

'Why, certainly, Doctor.'

'Well then, Cara; my quarters are very satisfactory and I had a most comfortable night, thank you. And thank you also for giving me this tour.'

'It's nothing,' she said lightly. 'I had the morning free anyway. The first reports on MICA won't be ready for a few hours yet.'

'When I must start earning my bed and board.'

'Not at all. Any a.s.sistance or advice you may give is purely voluntary; I thought that was made perfectly clear.'

'Oh, perfectly. But I do like to know where I stand in such matters.' He glanced at her with engaging innocence. 'There are so many subtle pressures that can be brought to bear on one, don't you think?'

Cara looked at him curiously, but at that moment daylight disappeared and the internal capsule lights came on automatically. The capsule had left the main Valley circuit line and the transparent tube wall had been replaced by solid rock.

'The s.p.a.ceport is up in the mountains beyond the end of the Valley,' she explained, 'but it doesn't take long to get there.'

In a minute the capsule began to slow, the tunnel opened out and they glided into another underground station. The door opened and they stepped on to a platform deserted save for a few freight cartons being loaded on to a cargo capsule and a couple of guards. The Doctor noted the latter and the security cameras with interest.

'Are these very evident precautions on my account?

Keeping a close eye on me in case I turn out to be a spy after all? Waiting to see if I get careless with my miniature camera, or have a bomb hidden under my sinister black cloak?' He grinned hugely and pulled a fold of his scarf mask-like across the lower half of his face.

Cara looked surprised, then chuckled. 'I hardly notice them most of the time, myself. And of course we trust you, Doctor, or else the Director would never have allowed you to come here. The security may have been stepped up because of the sightings of this mystery ship. We'll probably have an emergency shelter drill in a few days don't worry, directions will be given on all the public wall screens telling you what to do.'

'I'm sure it will be handled very efficiently,' the Doctor said sincerely. 'But has Deepcity actually ever been attacked?'

'No, never. We're well armed, of course, but our best weapon is concealment. If we were ever discovered, even if we beat off an initial attack, the Union would know there's something important here. They probably guess a facility like Deepcity must exist, and once they found it they'd throw everything they had against us. Even if they couldn't destroy us outright, all they'd need to do is enforce a blockade to prevent weapons leaving. We lose enough shipments through chance interceptions as it is; a siege would mean the end of our usefulness and probably the war.'

As they talked, they had made their way across to an observation window that looked out over the cold volcanic tube of the landing basin. A fan of service tunnels and hangars opened on to the opposite side, their worklights twinkling.

One ship was currently being rolled out on to the levelled floor of the shaft ready for launching. The Doctor ducked down to see the small circle of blue sky at the shaft's upper end. 'Does it ever get very busy here?' he asked.

'Sometimes nothing for days, then ships come and go so quickly the crews don't even disembark.'

'Do you travel yourself much?'

Cara wondered if he'd read her expression as she watched the ship being prepared. 'Not as much as I'd like, I admit. It sometimes gets, well, claustrophobic here. I've been to Alliance worlds a few times, but you can't make unnecessary journeys, of course security again. When we do get leave, which is essential for morale as you can guess, we take it on Ocea.n.u.s. It's picturesque, I suppose, but not a real world, if you see what I mean. It's not home.' She hesitated, then asked, 'Do you remember anything of your homeworld yet?'

'Just flashes,' he admitted. 's.n.a.t.c.hes of faces and scenes that I a.s.sume are from my homeworld. But I can't place them in any context, and without that they make very little sense.'

He took a key from his pocket and held it up for her to see. 'I have this but no lock for it to open. Perhaps it fits the door of my own house. Rather like the problem with my mind, but reversed. There I can't find the right key for the lock.

Somewhere there's a word that will make everything fall into place. At least, I hope there is.'

They returned to their capsule. It reversed and headed back the way it had come, rejoined the main tube line and then made a long curve around the head of the Valley. As they sped along the side of the tunnel it opened out again, giving a magnificent view of the open expanse of the Valley floor, the fringe of forest around its foothills, the unbroken sheer wall of encircling peaks rising high above them, cut through by the occasional white threads of waterfalls, all under a blue sky dotted with feathery clouds.

'We're travelling along the other side from the main complex itself,' Tarron explained. 'This is where the fabrication plants and factory are situated dug into the cliff side like the rest, of course. You'll see them in a minute.'

'How many people are there in Deepcity?'

'About eleven thousand and growing steadily. Quite a few families were here when Landor was lost the City was always intended to be as complete and self-contained as possible. Those children have grown now and are having children of their own.'

'Well, it looks very pleasant and certainly s.p.a.cious enough for them all. At least fifty kilometres long, I'd say, and you can always drill more tunnels.'

'Try it for twenty years, Doctor. Hidden away on some nameless planet which you can never explore because you can't leave the only shielded location. Looking up at nameless stars at night from a world you've never even seen from s.p.a.ce because you come and go in closed ships. Do you realize that s.p.a.ceship crews who have to know this planet's coordinates, are subconsciously conditioned to mindwipe or suicide if they are captured.'

'What you don't know you can't tell, I suppose?'

'It's necessary but is it an ideal place to bring up children? Still, they seem happy enough. Perhaps what they never knew they don't miss.'

'A remarkably adaptable species, h.o.m.o sapiens h.o.m.o sapiens astronauticus astronauticus, as I've always said. One of my favourites.'

Cara smiled uncertainly. 'I keep forgetting you're not I mean, is that really what you think of us?'

The Doctor frowned. 'I think so most of the time, anyway.'

The tube dived into the rock once more and the capsule glided into the factory station.

The multiple production lines ran through vast subterranean halls for five kilometres. Raw materials entered at one end and finished articles ranging from handguns to tanks emerged at the other, the entire process being monitored by a small workforce of humans and robots. The whine, clatter and hiss of a thousand machines filled the air with a constant drone of sound. It always put Cara in mind of the combs in an archaic beehive, even though she knew it was a strange parallel to draw between honey and instruments of war. They proceeded along the observation gantry until they reached the end of the line and looked down on to stacked cartons of hand weapons, rows of tanks with twin energy cannon, battle crawlers and gleaming ranks of motionless synthonic troopers waiting for shipment.

'Is that shape really efficient in combat?' the Doctor wondered, pointing to the troopers.

'The humanoid form is quite adaptable, as you said earlier, but there is also a psychological factor. The Averonians are also humanoid, and they supply similar synthoids to other members of the Union sometimes our pirated and copied models. By producing equivalent devices we counter the image of their machines, and remind the rest of the Alliance that humans are still part of this war, even if we haven't got the manpower to fight directly. No, that's not quite right: our navy is still out there. Somewhere there may be a starship production centre like Deepcity, but its location is even more secret than this place, if that's possible. n.o.body asks.'

They returned to the tube capsule. Tarron's fingers hesitated over the controls.

'Apart from the test zones out in the Valley floor, which we'll visit later, there's only the power plant at the other end of the Valley. Do you want to see that?'

'What type is it?'

'An old multiple torus magno-fusion stack. Normally we'd use solar receptors, but the area we'd need would show up from s.p.a.ce too easily.'

'Well, I always say when you've seen one multiple torus magno-fusion stack you've seen them all. I think we'll pa.s.s it by for the present.'

Tarron smiled and set the controls. The capsule sped away, curving round the opposite end of the Valley, and back along into the central complex again. They pa.s.sed the service centre and laboratories, and glided to a halt at the residential section stop once more.

'And that is our little world, Doctor,' Tarron said as the door opened. The Doctor gallantly helped her out on to the platform.

'Thank you for showing it to me. I hope I haven't kept you from anything important.'

Tarron studied her feet in embarra.s.sment for a moment, before looking up at him ruefully. 'Actually, showing you around was suggested to me by Dr Emberley. Contact with an outsider, you see. It's part of my therapy. I've had a touch of what we call "Deep Syndrome"...'

The Doctor listened patiently and sympathetically as she explained. But when she was done he suddenly looked perplexed. 'It's all right,' he rea.s.sured her, 'I don't mind. It's just that I never thought of myself as a patent medicine before.'

Elyze Brant entered lab three after lunch to find it in semi-darkness. The entire staff was gathered before the big screen at the front of the room which was displaying a dense jumble of complex formulae, equations and sketches of mechanical parts. More appeared even as she watched, being scribbled at remarkable speed. She saw the Doctor hunched over the input screen, writing and fielding questions from his evidently attentive audience at the same time.

After a minute Cara Tarron saw her, withdrew quietly from the group and came over, brushing back her hair tiredly as she did so.

'It looks baffling. Can you understand it?' Elyze asked simply.

Cara smiled. 'Some. Enough to know I don't know half as much as he does.'

'But you're sure it's genuine?'

'Oh, yes just very advanced.'

'I hope you're recording.'

'Of course.'

'And will it help with MICA?'

'Probably not.'

'But I thought you said '

'Yes, the Doctor's ideas are brilliant conceptually,' Cara explained, 'but to use them would mean redesigning half the existing systems, and we haven't got the time. We might incorporate some of them into the mark 2, but for the moment we'll have to make do with what we've got.'