The skeleton which Quallem and the trooper had found was in the first recreation area, slumped in the tattered frame of a deep chair. Symdon was studying the detector readouts with mounting concern.

Listrelle Quallem's eyes, behind her infra-scan goggles, were bright with anger. Life, survival, that had always been her aim, her motive at almost any cost. It made her burn with long-suppressed hatred to be so near a force that could control destruction so easily.

She activated the com-link with her voice-pattern. 'Boarding party to Icarus Icarus.'

High above them, a sound like the fluttering of wings echoed through the corridors.

In the near-silent and still TARDIS console room, the lights flickered once and dimmed again to a yellowish fog.

Had the Doctor been there, he would undoubtedly have known what to do about the small intrusion alert signal flashing on one of the panels of the hexagonal console. The time rotor was pulsing with a deep red that seemed to be draining the light from the rest of the room. A sound was gathering like a wind blowing scraps of paper across a deserted courtyard, or maybe the fluttering of a flock of migrating birds. An avalanche of noise, it tumbled through the corridors of time. The ship howled. Like vicious winds, agonies of torment.

In the space between the console and the interior door, the dark red seemed to gather into a billowing shadow. The shadow acquired depth, sleekness, reflection.

When the rushing wind died away, the console room contained the low, glossy shape of a black two-seater Porsche Turbo.

Chapter 4.

Vertices and Vortices On the podium on the bridge of the starship Icarus Icarus, the tall and long-limbed frame of Captain Romulus Terrin leant on the command rail and surveyed the bank of monitors that relayed images of Station Q4. He had already received Quallem's report and he was wondering, as he always did, about factors beyond the immediately obvious. There had been an attack, and so it had to be investigated and the perpetrators brought to justice that would be the same no matter what the nature of the murders. He had naturally experienced vicarious horror at Quallem's descriptions, but for him they now had more of a task than a mystery.

What he still did not understand was how the atmosphere regulators were still working properly.

At the Academy, Romulus Terrin had found that most of his trainers were living embodiments of the Peter Principle. Continually promoted for excellent achievement in their posts, they had risen in rank, were promoted again for outstanding achievement, until finally they reached a position where they moved neither up nor down. Everyone rising to the level of his or her own incompetence.

Once, during a lecture on tachyon control physics, he had risen boldly to his feet in a packed hall and, with his remote indicator, pointed out the crucial instability point in the lecturer's equation. Two years later, when giving his own lecture to a new year of cadets, he had snapped the screen dark and had gone into an elaborate conjuring routine, producing silver spheres apparently from nowhere and making gold fire leap from the desk. This had met with rapturous applause from the students, but the loudest ovation of all came after the last five minutes of the lecture, during which Terrin explained the scientific principles behind each and every one of the illusions. His students had left the hall dazzled not by sleight of hand but by his perceptions.

He was profoundly aware of his own lack of knowledge, of how small the accumulated wisdom of man could be in comparison with the vastness of the universe. One of his favourite writers, Andre Gide, had been interested in the idea of the man perceptive enough to know the limits of his intelligence, and Terrill subscribed keenly to this idea. With it in mind, he had refused an academic chair and had instead risen to the rank of starship captain, a role for which he considered himself eminently suitable. He had already once turned down the rank of admiral in order to avoid becoming a victim of the same principle that had trapped his tutors. And now, he was continually finding his knowledge and experience challenged on every single mission. That was how he wanted it to be. For Terrin knew that those who think they have understood the universe have the most closed minds of all.

He descended the white podium to stand beside his second officer. Darius Cheynor was in his thirties, somewhat younger than Terrin, and had a long, tanned face with a slender nose and deeply etched lines of worry. His night-black hair, years ago, had been shoulder-length and full of life, like that of a rock star or an actor, but now he had the regulation short-back-and-sides required to join the Terran Survey Corps.

'Why is it taking Quallem so long to locate two traces?'

Cheynor knew his commander well enough to appreciate that the question was rhetorical, and his large brown eyes did not leave the screen. 'She will, Captain. I've never known the Lieutenant-Commander to lose a trace.'

The communications TechnOp called to the Captain. 'Sir, Lightbase is requesting an update on our position.'

'Tell them we have no further information.'

'Sir?'

'Do it!'

'Yes, sir.'

The move had not surprised Cheynor. 'You want the ball all to yourself, Captain,' he murmured, but not disrespectfully.

Terrin voiced both their thoughts. 'This is right out of our league, Darius. If Lightbase know what we're dealing with, they'll pull us out straight away. Send us straight back for that de-commission. They might get round to sending a survey craft full of specialists in a month or so and then no one will ever find out what happened here.'

Cheynor knew that his Captain's unorthodox approach had paid off before. And so he wondered why he felt so uneasy.

In Oxford, there was sun and rain. The sun caught the silver threads of rainwater and made them glitter like a magical web across the town. Puddles shimmered with light and then were sliced into tatters of water by the wheels of buses. A rainbow arched from the dome of the Radcliffe Camera to somewhere far beyond the suburb of Cowley in the east, while the golden stone of the colleges, rain-darkened, was clear and sharp beneath a blue sky stained with the white and grey of clouds.

The new licensing hours were a blessing, thought Tom, even if the prices weren't. He carried the two brimming glasses of beer back to the table and smiled at Bernice, who looked at them somewhat disdainfully.

'So that's real ale,' she said.

Tom nodded. 'Cheers.'

'Oh. Cheers, then.' She took a sip. It was bitter and verging on the strength of sherry. She tried not to let her expression give too much away. 'Lovely,' she croaked. 'Very nice.'

'Here,' said Tom, casting a hand around the pub, 'is where C.S. Lewis and J.R.R. Tolkien used to get together with their mates. Like it?'

Bernice had already decided the place was full of smoke, populated with loudmouths and sportsmen, and really not her type of haunt at all. She was diplomatic. 'This, I take it,' she said, 'is the subversive tour of the town.'

'Quite right,' said Tom, and took another sip of his pint.

So this is what it's like, reflected Bernice. She hadn't seen a single gown or mortar-board yet, and had noticed only an average number of bicycles. The town seemed to bubble with life, but it was very different from the tangible academia she had expected to be able to sniff in the wind. Inhale in this Oxford, she decided, and you'd get a lungful of traffic fumes, whisky, dope and rain. She liked it, though. It had a kind of magic.

'If he's on form,' Tom said, 'then Professor Rafferty ought to be here before long.'

'Oh, yes?' Bernice answered. She smiled to herself. She half-hoped that Tom found the smile enigmatic. It was a way of distracting him from her true opinion of this beer stuff, she supposed, and she looked around the bar for another. 'Popular in this place, are you?'

'Hey. I'm everybody's favourite guy. Why do you ask?'

'Well, that girl at the bar's been giving you the eye ever since we came in. Or at least,' she added, as Tom swivelled to look with lightning reactions, 'I hope it's you, and not me. It's rather difficult to tell when she's wearing those things.'

The girl's mirrorshades reflected the vanishing daylight, which flickered briefly across them as she swivelled on her stool. She crossed her legs, affecting a nonchalant pose, as she sipped a mineral water.

'Never seen her before. More's the pity,' said Tom. He swung back round to Benny. 'You sure she was looking at me?'

'She's going,' said Bernice. 'Look.'

It was true. The girl had finished her drink, had picked up her reflective silver handbag and was heading for the door.

'Thomas, I think we've rumbled her,' Bernice murmured. She was welcoming the break from the TARDIS at the moment, but now she rather wished that the Doctor was there. Something about that girl spelt trouble.

The girl had to pass them at a distance of less than two metres to get to the pub exit. Something made Tom turn pale and take a deep gulp of his beer, not looking up until the coast was clear. Something had set him shivering, as if a blast of cold air had hit him.

'So,' said Bernice, ever observant, 'you do know her.'

He shook his head. 'I just had the strangest feeling. Like someone walking over my grave, you know...? Only more than that. Worse.'

'Worse?' Bernice's heart had started to beat a little faster.

'Yeah.' He took another deep and desperate gulp of beer, almost too quickly. 'I don't know. Something about her gave me the creeps. And there was that sound...'

Bernice had heard nothing. 'What sound?'

'Didn't you hear it? Like... like waves. No, it was more sort of fluttery, really... bats, maybe. Yeah.' He sat back in his chair, rubbed his eyes. 'It was bats. Definitely. Least, I hope it it was, and not me.' was, and not me.'

Bernice had already decided what to do. 'Drink up,' she said, and steeled her stomach for the onslaught ahead. 'Then we'll find Professor Rafferty.'

The manager of the Randolph Hotel in Beaumont Street was glad to see that the black car which had been obstructing the entrance had been removed. He had not seen it go, but then that was not his problem.

Meanwhile, in St Matthew's College, anyone entering the basement of its most modern block (considered an eyesore by Fellows and students alike) would have noticed that the college had acquired a new drinks machine in one shadowy corner. The girl who was walking up to it, though, knew it was there. She took a cursory look around her dark glasses flickering redly as if absorbing data before stepping into the back of the machine and disappearing.

After five minutes, she re-emerged and secured the unit with her remote locking device. She did not have the long-range laser in its briefcase this time, for she was hoping not to need it. Never one to come out unarmed, though, she hoped to rely, should the need arise, on the blaster disguised as an attack alarm in her clutch-bag.

Making her way to the surface via a spiral staircase, she emerged into the drizzle and began to stride across the quadrangle with an imperious step. The rainwater seemed to bounce off her hair and body as if repelled by some interior force.

The Professor of Extra-Terrestrial studies, ironically enough, was not that far away. He was deep in conversation with the Senior Dean beside the front lawn of the college. The Dean, who was doing most of the talking and was partially sighted, was not aware of the girl striding across the lawn behind them, and thus did not realize that he had lost the professor's already wandering attention.

The girl, who was breaking college rules by walking on the lawn, was crouching and, with her head bent towards the grass, sweeping one hand, palm downwards, over an area of the lawn about a metre and a half in diameter. Professor Rafferty squinted, while nodding in pretended agreement at the Dean's suggestion for the next Joint Council meeting. He saw now that the girl was brushing the air over a flattened area of grass. The area was perfectly square, and looked like the imprint of some heavy object. She seemed to be measuring the angles and lengths of the sides with her hands.

The Professor apologized for interrupting the Dean and strode forward to the edge of the lawn.

She looked up. The scan registered a humanoid. Height, one metre sixty. Physical age in Earth cycles, 57. Intelligence rating, high. Unarmed. She relaxed, allowed her long legs to unfold, taking her to her full height.

'Can I help you at all?' the Professor asked politely. He was aware that dealing with tourists was more the province of the Head Porter, but this one looked more like a student. Rafferty, despite the thought of his pint of bitter waiting in the Eagle and Child, was keen to fulfil his function as a moral tutor.

The girl smiled. It was like the snapping of an icicle. She came towards him, her high heels making sharp imprints in the lawn which would have endangered the head gardener's blood-pressure.

'I'm not sure.' Her voice was like unpolished silver. 'May I know whom I have the pleasure of addressing?'

He extended a hand, a little warily. 'Professor James Rafferty. Astronomy, astrophysics and, ah, other responsibilities.' The Professor still, through force of habit, tended to keep his exact title to himself unless pressed.

'You can call me Amanda,' she said.

She smiled.

But not with her shaded eyes.

The glo-ball bobbed in the darkness, casting a ghostly light on the Doctor. Ace followed, just as she had always done in the time before she had become more than just another piece of cargo for him. She wondered, still, what he knew about Space Station Q4, because he always knew more than he would tell. These days, he just expected her to guess.

Ace was beginning to recognize the creaking walkways and scarred bulkheads. They passed a prone skeleton which she definitely remembered seeing, and so it was no great surprise to her when they ended up back in the control centre.

The Doctor placed the ball on one of the inert consoles and his hands brushed the debris from the panels. 'I want to find out what happened here, Ace,' he murmured. Lit from below, his face looked menacing, troubled, like a man who had borrowed the powers of evil to make them fight each other for eventual good. 'These consoles could tell me... if only...'

It was Ace who saw stirrings in the shadows. 'Doctor '

The Doctor was juggling with wires behind a ripped-out monitor screen. 'It's just a matter of reanimating the passive inflectors but then what do I do next?'

'I'll tell you,' said the fair-haired officer, whom Ace had not quite spotted in time. His Derenna-24 handgun had been trained on the Doctor's left temple ever since the lime Lord had entered the room. 'You stand perfectly still and raise your hands.'

'That sounds like an excellent suggestion,' said the Doctor, who complied without turning his head. 'Terran Survey Corps, I assume.'

'You assume correctly.'

'A little late, if you ask me. A deaf Maston could have found us more quickly than you, in fact, more quickly than I could say, Ace, back to the TARDIS, now! Ace, back to the TARDIS, now!'

'I wouldn't,' said the man calmly, as Ace spun around to find another armed man in the doorway. 'Allow me to introduce myself. Lieutenant Albion Strakk, serving under Captain Terrin on the Starship Icarus Icarus. The gentleman in the doorway is Trooper Carden, who's been itching to shoot at something ever since we saw what happened to our colleagues. So I wouldn't even hiccup if I were you.' He spoke briefly into the microphone at his neck. 'This is Strakk. We've got them. In the control centre.' The response crackled in his ear. 'Now,' he said, 'why don't you just tell us what you're doing here?'

'You're very very nervous,' remarked the Doctor, risking a glance at Strakk. 'And you haven't shaved this morning. I don't like being threatened by frightened men, Lieutenant. The last one was a drunk in Victoria Bus Station before your time, of course, dreadful place anyway ' nervous,' remarked the Doctor, risking a glance at Strakk. 'And you haven't shaved this morning. I don't like being threatened by frightened men, Lieutenant. The last one was a drunk in Victoria Bus Station before your time, of course, dreadful place anyway '

'Carden.'

The trooper seemed to move with startling agility at Strakk's command, and grabbed Ace's hair, jamming his gun under her neck.

She struggled like an angry cat. 'We're on your side, you morons '

'Then prove it.' Strakk, the Doctor realized, was a tense young man doing a passable impression of a calm authoritarian. Beneath his eyes, the skin was grey and creased, while his blond hair bore an incongruous quiff of grey and white.

'It's very dangerous here,' the Doctor retorted. 'There are forces on this station that might surpass my own understanding, never mind yours.'

'I want identification.'

'I'm the Doctor, and this is my friend Ace.'

'Not good enough.'

'Well, that satisfies most people. Try under my hat.'

Strakk, suspicious, nodded to Carden, who tapped the hat off with his gun. Ace, rubbing her neck, muttered 'Bootbrain,' under her breath.

The lieutenant looked down the plastic strip of credit cards. 'United Nations Intelligence Taskforce? Rather behind the times, aren't we, "Doctor"? Interplanetary Visa... Prydonian Chapter Debating Forum... Oxford Union Society Oxford Union Society?'

'Life member,' offered the Doctor hopefully.

'Frankly, Doctor, I'm not impressed.'

'I might have known. Cambridge man, are you?'

'Moonbase Academy, actually. They teach you to shoot rather well in all gravity conditions. So please don't waste my time.'