Later, when the technology made it possible and the political conditions prevailing at the time made it advisable to quit that system, it had been fitted with fusion-powered steam rockets and ion engines to help propel it into interstellar space. Again due to those political conditions, it armed itself with up-rated signal lasers and a number of at least partially targetable mass launchers which doubled as rail guns. Some years later, scarred but intact, and finally accepted as personally sentient by its human inhabitants, it had been one of the first space-based entities to declare for the new pan-civilisational, pan-species grouping which was calling itself the Culture.

Over the years, decades, centuries and millennia that had followed, Phage had journeyed through the galaxy, wandering from system to system, concentrating on trading and manufacturing at first and then on a gradually more cultural, educatory role as the advances in technology the Culture was cultivating began to distribute the society's productive capacity so evenly throughout its fabric that the ability to manufacture almost anything developed almost everywhere, and trade became relatively rare.

And Phage Rock — by now recognised as one of a distinct category of Culture artifacts which were neither ships nor worlds but something in between — had grown, accruing new bits of systemic or interstellar debris about it as its needs required and its population increased, securing the chunks of metal, rock, ice and compacted dust to its still gnarled outer surface in a slow process of acquisition, consumption and evolution, so that within just a millennium of its transition from mine to habitat its earlier, original self wouldn't have recognised it; it was thirty kilometres long by then, not three, and only the front half of that initial body still peeped out from the prow of the knobbly collection of equipment-scattered mountains and expanded, balloon-like hangar and accommodation rotundae that now formed its roughly conical body.

Phage Rock's rate of accretion had slowed after that, and it was now just over seventy kilometres long and home to one hundred and fifty million people. It looked like a collection of craggy rocks, smooth stones and still smoother shells brought from a beach and cemented into a rough cairn, all dotted with what looked like a museum collection of Culture Equipment Through the Ages: launch pads, radar pits, aerial frames, sensory arrays, telescope dishes, rail-gun pylons, crater-like rocket nozzles, clamshell hangar doors, iris apertures and a bewildering variety of domes large and small, intact and part-dismantled or just ruined.

As its size and its population had grown, so had the speeds Phage Rock was capable of. It had been successively fitted with ever-more efficient and powerful drives and engines, until eventually it was able to maintain a perfectly respectable velocity either warping along the fabric of space-time or creating its own induced-singularity pathway through hyperspace beneath or above it.

Ulver Seich's had been one of the Rock's Founding Families; she could trace her ancestry back through fifty-four generations on Phage itself and numbered amongst her ancestors at least two forebears who were inevitably mentioned in even one-volume Histories of the Culture, as well as being descended from — as the fashions of the intervening times had ordained — people who had resembled birds, fish, dirigible balloons, snakes, small clouds of cohesive smoke and animated bushes.

The tenor of the time had generally turned against such outlandishness and people had mostly returned to looking more like people over the last millennium, albeit assuredly pretty good-looking people, but still, some part of one's appearance was initially at least left to luck and the random nature of genetic inheritance, and it was a matter of some pride to Ulver that she had never had any form of physical alteration carried out (well, apart from the neural lace of course, but that didn't count). It would have been a brave or deranged human or machine who told Ulver Seich to her face that the give-or-take-a-bit human-basic form was not almost unimprovably graceful and alluring, especially in its female state, and even more especially when it was called Ulver Seich.

She looked round the room the drone had brought her to. It was semicircular and moderately big, shaped like an auditorium or a shallowly sloped lecture hall, but most of the steps or seats seemed to be filled with complicated-looking desks and pieces of equipment. A huge screen filled the far wall.

They'd entered the room through a long tunnel which she'd never seen before and which was blocked by a series of thick, mirror-coated doors which had rolled silently back into recesses as they'd approached, and revolved back into place behind them once they'd passed. Ulver had admired her reflection in every one of them, and drawn herself up even straighter in her spectacular violet gown.

The lights had come on in the semicircular room as the last door had rolled back into place. The place was bright, but dusty. The drone whooshed off to one side and hovered over one of the desks.

Ulver stood looking round the space, wondering. She sneezed.

"Bless you."

"Thank you. What is this place, Churt?" she asked.

"Emergency Centre Command Space," the drone told her, as the desk beneath it lit up in places and various panes and panels of light leapt up to waver in the air above its surface.

Ulver Seich wandered over to look at the pretty displays.

"Didn't even know this place existed," she said, drawing one black-gloved finger along the desk's surface. The displays altered and the desk made a chirping noise; Churt Lyne slapped her hand away, going 'tssk' while its aura field flashed white. She glowered at the machine, inspected the grey rim of dust on her finger tip, and smeared it on the casing of the drone.

Normally Churt Lyne would have slicked that part of its body with a field and the dust would just have fallen off, having literally nothing to cling to, but this time it ignored her and just kept on hovering over the desk and its rapidly changing displays, obviously controlling both it and them. Ulver crossed her black-gloved arms in annoyance.

The sliding panels of lights hanging in the air changed and rotated; figures and letters slid across their surfaces. Then they all disappeared.

"Right," the drone said. A maniple field coloured formal blue extended from the machine's casing and dragged a small sculpted metal seat over, placing it behind her and then shoving it quickly forward; she had no choice but to plonk down into it.

"Ow," she said, pointedly. She adjusted her bustle and glared at the drone but it still wasn't paying attention.

"Here we go," it said.

What looked like a pane of brown smoked glass suddenly leapt into existence above the desk. She studied it, attempting to see her reflection.

"Ready?" the drone asked her.

"Mm-hmm," she said.

"Ulver, child," the drone said, in a voice she knew it had spent centuries investing with gravitas. It swivelled through the air until it was directly in front of her.

She rolled her eyes. "Yes? What?"

"Ulver, I know you're a little-"

"I'm drunk, drone, I know," she told it. "But I haven't lost my wits."

"Well, good, but I need to know you're fit to make this decision. What you're about to see might change your life."

She sighed and put her gloved elbow on the surface of the desk, resting her chin on her hand. "I've had a few young fellows tell me that before," she drawled. "It always turns out to be a disappointment, or a joke of the grossest nature."

"This is neither. But you must understand that just seeing what I'm about to show you might give Special Circumstances an interest in you that will not pass; even if you decide you don't want to join Contact, or even if you do but you're still refused, it is possible they might watch you for the rest of your life, just because of what you're about to see. I'm sorry to sound so melodramatic, but I don't want you to enter into anything you don't understand the full implications of."