“And did you find it?”

Fassin was silent for a moment. Setstyin watched the little gascraft make a show of looking around the library. “Is this place quite private? I mean, secure?” Fassin asked.

“I should hope so,” Setstyin said. “Why?”

“Can we signal, rather than speak, Setstyin?” Fassin asked. “It’s not as easy for me as speaking, these days, so bear with me, but it is more secure.”

· Of course, the Dweller sent.

· Well, I think I might have found the Transform, the human sent carefully.

· Really?

·… Really.

· You will understand if I am a little sceptical.

· Only natural.

· Where did you find this Transform?

· On the body of that dead Dweller, in the Ythyn Sepulcraft, on the far side of the galaxy.

· Ah-hah. What ever was it doing there?

· It was in a sort of safekeep box.

· And who would put it there?

· I don’t know.

· And what did this Transform consist of?

· An equation.

· As in mathematics?

· That’s right. It looked a bit like what some people had come to expect it to look like — a code and a frequency for a broadcast signal of some sort — but in the end it was just an equation.

· And this was supposed to unlock the List thing?

· That’s what we were all told.

· Hmm. But?

· But, when I solved the equation, guess what?

· Oh. Ah, I have no idea. Do tell.

— It came out at nothing. Zero. The Transform turned out to be, in effect, a contrived mathematical joke.

Fassin signalled a laugh.

Setstyin shared the amusement. — I see. So, if this is what you were sent to look for, you might be said to have succeeded in your mission, though not in the manner you might have wished. Yes?

· Those were pretty much my thoughts, too.

· Well, at least you missed all the unpleasantness of this inva-sion your people have suffered. Thinking of you, I’ve been watching the situation. It all looks quite distressing. And still going on. And affecting us, too. There were explosions around Nasqueron just yesterday. Did you see any of them?

· I did. I hear there’s a rumour that the invaders might be about to pull out.

· Possibly our planetary defence people again. There have been the usual denials, of course. Umm, I’m afraid even if I did know more, I couldn’t talk about it. You understand.

· Of course. So, Fassin sent. — You don’t know anything about these wormholes? You’ve never heard of them? I just thought, you being so well connected…

· All news to me, Fassin. Possibly some small group might have control of such things, though I find that hard to believe, frankly.

· Ah, well, Fassin sent. He was silent for a few moments.

· Yes? Setstyin sent.

· Well, Fassin replied slowly. — I did have an idea.

· An idea? Indeed.

· What if the Transform answer wasn’t a joke?

· Not a joke? But it’s zero. What use is that?

· You see, Fassin sent, and the little gascraft nudged forward a fraction on the dent-seat, closer still to Setstyin, — I had thought, what use would an equation be, after all this time? How could it tell you anything useful? A frequency and a code to be broadcast on it was the only thing that really made sense; then these worm-

holes could be hidden anywhere in the named systems and only activate themselves when needed. So the fact it was an equation at all made it kind of pointless even before it was worked out.

· I’ll take your word for it, Setstyin told the human. — You are rather losing me here, but it all sounds terribly convincing.

· And then there was all that absurd twisting and spiralling when I was aboard the ship heading through the wormhole portals. Being cut off from external senses seemed obvious enough, but why the spiralling?

· Umm, yes, in the ship. I see.

· And just the fact that all of Dweller society does seem like a proper civilisation.

· Now you really are losing me, Fass.

· And you obviously possess technologies that we still haven’t understood.

· Well, we’re like that. Us Dwellers, aren’t we? Oh dear, I think all this is upsetting my balance.

· You see, if the Transform means what it says, what it’s saying is that the adjustment you have to make to each entry on the Dweller List to find out where the wormhole portals are in relation to those original locations named is…

Fassin held the little gascraft’s working arm out, inviting Setstyin to answer.

The Dweller ruffled his sensory mantle, which had gone a slightly odd colour. — I’m sorry, Fassin, I feel positively dizzy.

· Nothing! Fassin sent. — The adjustment is zero.

· Is it? Is it really? I’m sure this is fascinating, really.

— And what was the original List based on, what did it give?

Again, he gave the Dweller a chance to answer, but he didn’t.

— It gave the location of Dweller-inhabited gas-giants! Fassin put a sort of triumphalist joy into the signalled sentence.

— I see. I do feel slightly off, Fass. Do you mind if I… ?

Setstyin rose, wobbling slightly, and roted over to his desk.

He started opening lockers and drawers, then glanced up. “Keep going, keep going,” he said. “I have my medication in here somewhere.”

The Dweller signalled to his servant while he looked through the drawers, keeping his signal pit below the level of the desk, out of sight of the human in his gascraft.

— Was Mr Taak armed in any way?

After a moment: — No, sir. The house checked automatically, naturally. Aside from his manipulative devices, he is unarmed.

— I see. That’s all.

The arrowhead swivelled to keep line-of-sight with the Dweller.

— The List doesn’t need the Transform, Fassin told Setstyin.

— All you need to know is that the planets are the location.

— Really? Indeed. And how can that be?

The little gascraft rose up into the air above the dent-seat.

— Because your wormhole portals are inside your planets,

Setstyin, Fassin sent calmly.

The Dweller froze, then opened one last drawer. “But that’s ridiculous,” he said aloud.

“Right in the centre,” Fassin continued, also speaking out loud now. “Probably of every single gas-giant you guys inhabit. There were only — what? — two million when the List was drawn up, that right? But that was long ago, and it was a historical document even then. I wouldn’t be at all surprised to hear you’d connected up every last Dweller planet by now.”

“I’m sorry, Fassin,” Setstyin said. “You wouldn’t convince a child with this. Everybody knows you need a flat region of space to make a wormhole portal work.”

“Ah, that’s the beauty of it. The very centre of a planet is flat,” Fassin said. “Right in the very centre of a planet, of any free-floating body — sun, rock, gas-giant, anything — you’re being pulled equally in all directions. It’s just like being in orbit round a world and feeling weightless. The only problem, of course, is keeping a volume of space open in the core of a planet or a sun or whatever in the first place. The pressure is colossal, almost beyond belief, especially in a gas-giant the size of Nasq., but in the end it’s just engineering. Hey, you guys have had ten billion years to get good at that sort of stuff. Anything that isn’t impossible you learned to do easily when the galaxy was a quarter of the age it is now.

“So you don’t need to position portals in space where anybody could see them or use them or attack them, you don’t even need to leave your own planet to access them, you just head for some well-hidden shaft that leads you down to the very centre of the world. Maybe at the poles. That would be an obvious kind of place. And if you’ve got somebody aboard your ship who might be keeping track of where you’re going somehow, you just throw in all these crazy spirals and flash some screenage of space into wherever you’re keeping them, so they never can tell they’ve gone down, not up, and have sunk into the core, not flown out into space.”