CITY IN THE SKY

PROLOGUE

There are very few occupations more tranquil and relaxing than sitting and idly contemplating a fishing line, under a big blue sky on the banks of a placid English river.

Then again, there are few more frustrating trials of endurance than having to sit and bubble inside, seething with indignation, hatred, self-pity and contempt, when one's companion is endeavouring to let the day slip away, un-remarked.

In this case the angler was, of course, the Doctor. He had a line attached to the end of his umbrella, which lay balanced across his knees whilst he lay prone on the grassy bank, straw hat pitched over his face.

The young woman sitting, knees up to her chest, hugging herself tightly, was Ace. To her mind the Doctor had decided to inflict a cruel and unusual punishment on her, dragging her away from Mike Smith's funeral to sit on the banks of the River Rowley. The funeral might have been grim but she would have had the company of other people, instead of having merely her own sombre thoughts.

She moodily threw a stone into the slow, green waters of the Rowley, creating a notable "plop".

'Ace!' scolded the Doctor. 'You'll scare the fish away.'

Some hope! she nearly replied.

'Scumbag,' she added, accidentally speaking aloud.

The Doctor tipped his hat back, looking at her with a touch of ancient wisdom.

'Oh dear. I did hope bringing you here might quieten your troubles a little, relax a bit, contemplate the beauties of nature. Recriminations because of Sergeant Smith, eh?'

It wasn't her fault that Mike had turned out to be a neo-Nazi scumbag, after she'd fallen for him big time. She ought to be glad he was dead, traitor that he was, except she couldn't quite bring herself to believe it.

Recognising the symptoms of a heavy heart, the Doctor hauled his line in and sat up. So much for quiet contemplation! Ace needed distracting.

'A tragedy,' he murmured. ' "Send not to ask".' He looked sideways at the young woman, picking up her skin tone, body posture, involuntary movements and vocal stress. 'If he'd known you longer he'd have changed his opinions.'

Another muttered insult flew to Ace's lips.

'Nobody is truly irredeemable, Ace,' he gently chided her.

'Not even the Daleks?' she shot back. The Doctor smiled ruefully and shook his head.

'Ah, the Daleks. Extinct. Dead as the Dodo. What's that aphorism they use in Andromeda? "Gone the way of the Wirrn". Actually - ' and he remembered another youthful companion. 'Actually the Daleks would have been redeemable, Ace. They were playful and as harmless as kittens when infused with Human Factor.'

'What's "Wirrn"?' asked Ace, picking up on one of several hints the Doctor had carefully and subtley seeded his conversation with. Distraction, after all, needed to avoid looking like distraction.

'The Wirrn. An alien race of insect origins, from the Andromeda Galaxy. Big as bears, and considerably more dangerous.'

Picturing a fly or wasp ten feet tall made Ace feel creeped-out. She wrinkled her nose before coming back with an observation.

'Andromeda's really far away, isn't it?'

'Quite. Two and a half million light years away. I only travel there when necessary – bit of a commute when the Tardis isn't as reliable as you'd want her to be.'

For several seconds the only sounds to be heard were a distant jet airliner, the ripple of the river and muted calls from moorhens amongst riverbank reeds. The Doctor felt pleased – Ace was diverted, mulling over what she'd been told.

'How come they're extinct?' she began, before letting her arms fall to her sides and trying to frown at her mentor as realisation dawned. 'You've changed the subject!'

He chuckled.

'Yes indeed. Quick of you to notice – your observational skills are improving. Very well: the Wirrn. In the thirtieth century Earth is going to be devastated by solar flares. A fraction of the human race enters orbital suspended-animation, whilst most go underground to live in subterranean cities. Another fraction heads out into deep space, which includes Andromeda -'

- and what a struggle that had been when they got there. Convinced that Earth-bound humanity was doomed, the Gal Sec human colonists had offered no quarter when they came across the Wirrn, the dominant life-form in Andromeda, and who themselves attacked the unfamiliar alien intruders in unrelenting conflict. A conflict that took place across almost eighteen per cent of the galaxy, a truly colossal war that lasted for nine hundred years. By the end of it the Wirrn were wiped out.

'But one of them, and a Queen at that, must have stowed away on a Gal Sec ship that returned to the Solar System,' finished the Doctor. 'This, the last of the Wirrn, sought revenge, and Space Station Nerva was the perfect environment for it. Sterile, so no alien pathogens to worry about. No weather. Nothing living or conscious to thwart it, and six thousand defenceless humans to assimilate or lay eggs in.'

This time Ace made a sound to go with her wrinkled nose.

'Ewww! Horrid. Mind you, that's a lot of people. Six thousand of them.'

The Doctor took up a characteristic pose, resting his chin on his upright umbrella.

'Six thousand people's nothing, Ace.'

'It is too!' she replied, with feeling. She felt compelled to defend human endeavour. 'I know there's only been a few on Mir and Skylab. Six thousand's a lot, Professor.'

Recognising this casual address, the Time Lord realised Ace wasn't brooding any more on the past, on funerals or Mike Smith.

'Try one hundred and fifty thousand, Ace.'

She looked incredulous.

'Honestly, quite true, Ace. The planners behind Nerva knew their project would succeed because their far less-advanced ancestors put the equivalent of an entire city into orbit, and kept them up there for decades and decades.'

'When?'

'About a century from now.'

Typically, one question begat another from the young woman. All thoughts of death or being unlucky in love were forgotten.

'Okay, why did they do it?'

A sigh was her only reply.

'Come on, Professor, you can't tease me with half a story!' She paused. 'Or do you want me to fill the gaps in by myself?'

The Doctor turned to look at her, looking only slightly less-puzzled than she did.

'It had to do with the Big Crash, the Great Northern War and the Human Salvation Project,' he said, before stopping. 'I did plant some seeds about possible survival methods at the time, but didn't stay to see if they were ever taken up. Do you know, I never visited the Arc-ipelago, not once. Nor Earth at the time. Bit of a mess. I stayed clear until the background count diminished to a safe level.'

'Hang on,' complained Ace. 'What are all these things you've just introduced?'

Shrugging, the Doctor got to his feet and offered his companion a hand up.

'I don't know. Shall we go and find out?'

'Cool!'