Personally, Genar-Hofoen had always thought it was a reasonable enough rule, although along with a lot of people over the years he'd long suspected that one of the main reasons for its existence was that it suited the purposes of the Culture's Minds in general, and those in Special Circumstances in particular.

Thanks to that taboo, everybody in the Culture could keep secrets to themselves and hatch little schemes and plots to their hearts" content. The trouble was that while in humans this sort of behaviour tended to manifest itself in practical jokes, petty jealousies, silly misunderstandings and instances of tragically unrequited love, with Minds it occasionally meant they forgot to tell everybody else about finding entire stellar civilisations, or took it upon themselves to try to alter the course of a developed culture everybody already did know about (with the almost unspeakable implication that one day they might do just that not with a culture but with the Culture… always assuming they hadn't done so already, of course).

"What about the people on board the Culture ship?" Genar-Hofoen asked.

"They knew as well, of course, but they kept quiet, too. Apart from anything else, they had two weirdnesses on their hands; they assumed they had to be linked in some way but they couldn't work out how, so they decided to wait and see before they told everybody else." Tishlin shrugged. "Understandable, I suppose; it was all so outlandish I suppose anybody would think twice about shouting it to the rooftops. You couldn't get away with such reticence these days, but this was then; the guidelines were looser."

"What was the other unusual thing they found?"

"An artifact," Tishlin said, sitting back in the seat. "A perfect black-body sphere fifty klicks across, in orbit around the unfeasibly ancient star. The ship was completely unable to penetrate the artifact with its sensors, or with anything else for that matter, and the thing itself showed no signs of life. Shortly thereafter the Problem Child developed an engine fault — something almost unheard of, even back then — and had to leave the star and the artifact. Naturally, it left a load of satellites and sensor platforms behind it to monitor the artifact; all it had arrived with, in fact, plus a load more it had made while it was there.

"However, when a follow-up expedition arrived three years later — remember, this all happened on the galactic outskirts, and speeds were much lower then — it found nothing; no star, no artifact, and none of the sensors and remote packages the Problem Child had left behind; the outgoing signals apparently coming from the sentry units stopped just before the follow-up expedition arrived within monitoring range. Ripples in the gravity field near by implied the star and presumably everything else had vanished utterly the moment the Problem Child had been safely out of sensor range."

"Just vanished?"

"Just vanished. Disappeared without trace," Tishlin confirmed. "Most damnable thing, too; nobody's ever just lost a sun before, even if it was a dead one.

"In the meantime, the General Systems Vehicle which the Problem Child had rendezvoused with for repairs had reported that the GCU had effectively been attacked; its engine problem wasn't the result of chance or some manufacturing flaw, it was the result of offensive action.

"Apart from that, and the still unexplained disappearance of an entire star, everything was normal for nearly two decades." Tishlin's hand flapped once on the table. "Oh, there were various investigations and boards of inquiry and committees and so on, but the best they could come up with was that the whole thing had been some sort of hi-tech projection, maybe produced by some previously unknown Elder civilisation with a quirky sense of humour, or, even less likely, that the sun and all the rest had popped into Hyperspace and just sped off — though they should have been able to observe that, and hadn't — but basically the whole thing remained a mystery, and after everybody had chewed it over and over till there was nothing but spit left, it just kind of died a natural death.

"Then, over the following seven decades, the Problem Child decided it didn't want to be part of Contact any more. It left Contact, then it left the Culture proper and joined the Ulterior — again, very unusual for its class — and meanwhile every single human who'd been on board at the time exercised what are apparently termed Unusual Life Choices." Tishlin's dubious look indicated he wasn't totally convinced this phrase contributed enormously to the information-carrying capacity of the language. The image made a throat-clearing noise and went on: "Roughly half of the humans opted for immortality, the other half autoeuthenised. The few remaining humans underwent subtle but exhaustive investigation, though nothing unusual was ever discovered.

"Then there were the ship's drones; they all joined the same Group Mind — again in the Ulterior — and have been incommunicado ever since. Apparently that was even more unusual. Within, a century, almost all of those humans who'd opted for immortality were also dead, due to further «semi-contradictory» Unusual Life Choices. Then the Ulterior, and Special Circumstances — who'd taken an interest by this time, not surprisingly — lost touch with the Problem Child entirely. It just seemed to disappear, too." The apparition shrugged. "That was fifteen hundred years ago, Byr. To this day nobody has seen or heard of the ship. Subsequent investigations of the remains of a few of the humans concerned, using improved technology, has thrown up possible discrepancies in the nanostructure of the subjects" brains, but no further investigation has been deemed possible. The story was made public eventually, nearly a century and a half after it all happened; there was even a bit of a media fuss about it at the time, but by then it was a portrait with nobody in it: the ship, the drones, the people; they'd all gone. There was nobody to talk to, nobody to interview, nothing to do profiles of. Everybody was off-stage. And of course the principal celebrities — the star and the artifact — were the most off-stage of all."

"Well," Genar-Hofoen said. "All very-"

"Hold on," Tishlin said, holding up one finger. "There is one loose end. A single traceable survivor from the Problem Child who turned up five centuries ago; somebody it might be possible to talk to, despite the fact they've spent the last twenty-four millennia trying to avoid talking."

"Human?"

"Human," Tishlin confirmed, nodding. "The woman who was the vessel's formal captain."

"They still had that sort of thing back then?" Genar-Hofoen said. He smiled. How quaint, he thought.

"It was pretty nominal, even back then," Tishlin conceded. "More captain of the crew than of the boat. Anyway; she's still around in a sort of abbreviated form." Tishlin's image paused, watching Genar-Hofoen closely. "She's in Storage aboard the General Systems Vehicle Sleeper Service.

The representation paused, to let Genar-Hofoen react to the name of the ship. He didn't, not on the outside anyway.

"Just her personality is in there, unfortunately," Tishlin continued. "Her Stored body was destroyed in an Idiran attack on the Orbital concerned half a millennium ago. I suppose for our purposes that counts as a lucky break; she'd managed to cover her tracks so well — probably with the help of some sympathetic Mind — that if the attack hadn't occurred she'd have remained incognito to this day. It was only when the records were scrutinised carefully after her body's destruction that it was realised who she really was. But the point is that Special Circumstances thinks she might know something about the artifact. In fact, they're sure she does, though it's almost equally certain that she doesn't know what she knows."