Poseidon's Wake

by Alastair Reynolds

  ‘Like some sort of parasite?’ Dr Andisa asked.

  ‘I think we may presume that the relationship is mutually consensual and to the benefit of both host and symbiote. That Kanu has willingly allowed Swift to co-opt part of his neural network. What do we know of Kanu? He was an ambassador to the machines on Mars. I do not think these two facts are unrelated.’

  ‘Then who – or what – is Kanu acting for?’ Goma asked.

  Eunice wriggled in her restraints. ‘Are you going to let me out of this chair any time soon?’

  ‘No,’ Vasin said. ‘You acted without authorisation. You took a foolhardly gamble with thousands of lives, both human and Tantor.’

  ‘I took a gamble to stop someone else taking a worse one. I gave Kanu an opportunity to challenge Dakota, with Swift’s reassurance that he had the means to take control of Icebreaker. Swift explained that there would be some kind of restart of Icebreaker’s systems, which is what we’ve just witnessed. Clearly, the humans are back in charge. That’s why the ship is making such a concerted effort to reverse course.’

  ‘So you’ve succeeded,’ Ru said.

  ‘It’s starting to look that way. A little closer to the bone than I’d like, but what are nerves for, if not to be frayed?’

  ‘You haven’t even considered the lives on Zanzibar. The Friends, the Tantors – they’re not even a part of your thinking any more. You’ve moved them off the board and forgotten about them. We were all wrong about you.’

  She looked at Ru with an expression of pleasant interest. ‘Were you, my dear?’

  ‘You’re still a fucking machine.’

  ‘Well, thank you for that considered opinion. Shall I be equally candid, then? I don’t care. I expected to die. I expected to be torn limb from limb or stuffed into the nearest airlock. I expected that and I knew I had to act anyway – that nothing else was going to work. So spare me your lofty human sanctimony, because until you’ve been through the Terror, you have no idea what’s at stake. And if you had an idea, even the tiniest grain of an inkling, you’d know full well that my actions were not only necessary but the very least that needed to be done. If I could have destroyed Icebreaker, do you think I’d have hesitated?’

  ‘No,’ Ru said. ‘I don’t suppose you would have.’

  ‘Then we’re getting somewhere.’

  But Vasin said quietly, ‘You say the humans should be back in charge by now.’

  ‘Yes.’

  ‘Then explain this.’

  Over the next few hours they watched Kanu’s ship fall into the barricade of moons. The course correction had been going well, the engine signature reading clean and steady, no cause for concern even as Icebreaker topped out at a crushing three gees of reverse thrust. Then it dropped down to a single gee even though Icebreaker still had far too much residual motion in the direction of Poseidon. Their first guess was some kind of engine failure, but nothing in the data hinted at anything other than a smooth, controlled reduction of power – a deliberate change of plans.

  They waited to see if this was a temporary adjustment, soon to be corrected. Eunice was as bothered about it as the rest of them – her confidence in both herself and Swift severely damaged. More than anything, that was the deciding moment when Goma put aside the last trace of doubt that they were dealing with a human being. No matter what Ru thought, no machine would have shown such consternation at this change in circumstances. A robot would have absorbed the altered parameters without the slightest sense of betrayal or personal failure.

  Soon they had the confirmation they had been dreading.

  ‘This is Kanu. I hope you can read me. Shall I begin with the good news or the bad?’

  They were close enough for real-time communications again. His face loomed large, but now the effects of gravity made him look drawn and fatigued, older and wiser by many years.

  ‘Go ahead, Kanu,’ said Captain Vasin.

  ‘Nissa and I have complete control of Icebreaker. Tell Eunice – if she isn’t already listening in – that she and Swift did a very good job with their scheme for Zanzibar. They can be proud of their achievement. That doesn’t mean I approve. Right now I’m not certain what approval would say about any of us. Was it an act of kindness or cruelty? I’m not exactly sure.’

  ‘Nor are we,’ Vasin said. ‘Horrified, and awed – there’s no doubt about that. But was it the right thing to do? I’d say it was, if we couldn’t see you continuing to Poseidon.’

  ‘We ran into a local complication which neither Swift nor Eunice anticipated. We had the means to turn Icebreaker around and were in the process of doing so, but it was too hard on the Tantors. They couldn’t take the gee-load. If we’d carried on, we are fairly sure they would have died.’

  ‘Just a second,’ Eunice said, now free of her chair but still shackled at the wrists. ‘You can turn around, but you’re not going to?’

  ‘We won’t murder them. That’s what it would have been. You can see that, can’t you?’

  ‘You owe them nothing,’ Eunice snapped back. ‘Especially not Dakota. You’re not dealing with an elephant, Kanu, or even a Tantor – you’re dealing with an alien intelligence that just happens to be using her body.’

  ‘I can understand why you feel that way. But if there’s a shred of humanity left in any of us, we can’t place our own lives over theirs.’

  ‘That’s very noble of you, but it’s not just your lives on the table here. Turn your ship around.’

  ‘It’s too late for that now, Eunice – you know that as well as we do. We’re committed to Poseidon now, for better or for worse. It’s going to be hard, in more ways than one.’

  ‘Not just hard,’ she said. ‘Suicidal.’

  Kanu’s gravity-strained face managed a weak smile. ‘Yes. I’m aware of that. And believe me, I don’t like it for a second. But we’re not totally out of chances. We’ll see how we weather the moons. Even if we survive passage through them, we’ll still have the problem of atmospheric entry. We’re moving a little too quickly for safe planetfall, and Icebreaker certainly isn’t designed to cope with the stresses. But we have our lander, Noah. It’s large enough to accommodate all of us, and once we’re through the moons it might get us down to the surface, and maybe we can reach one of those wheels, see what we make of it. But we’re under no illusions about getting back out again. Since we’re going in, though, we may as well make the best of it. We’ll be gathering all the information we can and doing our best to share it with you. But you’ve done your part now.’

  ‘What are you suggesting?’ Vasin asked.

  ‘Turn around. You gave it your best shot and I think we can both agree there need be no hard feelings. There’s nothing to be gained from debate now – the time for that has passed. We have no option; we’re going in, and we’ll endeavour to be your eyes and ears. I was about to wish you the best in forging ties with Zanzibar, but I keep forgetting that won’t be necessary – it isn’t here any more. Will you be all right? Can you get back to your starship?’

  ‘Don’t worry about us,’ Vasin said. ‘We have everything we need, and even if we didn’t, there’s still Eunice’s camp on Orison. We’ll return there to help the surviving Tantors – but not until we’ve done all we can for you.’

  ‘There’s nothing to be done. But Nissa and I appreciate the sentiment.’

  ‘Let me speak to Swift,’ Eunice said.

  ‘So that you can talk him into destroying Icebreaker in a moment of glorious self-sacrifice?’ Kanu smiled sadly. ‘As it happens, we’ve already discussed that, and maybe it wouldn’t be such a bad idea. But we’re not quite ready to face total oblivion just yet. Not while there’s a chance to learn something new. It’s the reason we came here, after all – to gather knowledge. And if, collectively, none of us is quite up to the measure of the M-builders – well, then it looks to me as if we’re all doomed anyway. But I’m han
ding no one my head on a plate.’

  ‘Tell Swift—’

  ‘Swift says that he’d welcome the exchange of further views, but for the time being we have a little preparation of our own to be doing. I’ll talk to you all on the other side of the Terror. Wish us well, won’t you?’

  The channel was closed, but they could still track Icebreaker clearly enough to observe its progress. They watched it fall deeper, slowing all the while but never enough, and they ran their own simulations for atmospheric insertion assuming a spread of assumptions for the capabilities of Kanu’s ship.

  Until Eunice drew their attention to one of the moons, now veering out of its orbit like a marble that had wandered out of a groove.

  ‘There’s always one,’ she said. ‘The chasing moon. It’ll be on them soon enough. And if Kanu has an ounce of sense – or if he listens to Dakota – he’ll know better than to try to escape.’

  ‘What will the moon do?’ Goma asked.

  ‘Swallow them. And cut them open. Crack their spines and read them like books. But don’t worry. It’s less painful than it sounds.’

  CHAPTER FORTY-SIX

  Kanu had been wrong about the moons, but he could be forgiven for that. Even Icebreaker had been confused by them, its sensors registering them only as small, black, mathematically spherical bodies. As one of the objects closed upon them, though, he began to grasp his error. The moon was only spheroidal in the way a spinning coin defines the shape of a sphere. The moon was winding down – turning ever more slowly on its axis. The rotational speed was still almost too fast for the naked eye to interpret, but now at least the ship was having less difficulty.

  He stared at the images and overlays on the bridge display – the patchwork of analysis and interpretation the ship was doing its best to offer.

  The chasing moon was a thin grey ring of the same diameter as the implicit sphere – about two hundred kilometres across, which in turn made it about the same size as the wheels on Poseidon. The width and thickness of the ring were also in proportion to the wheels. They would have better data as the moon reduced its spin even further, but on the evidence presented so far, Kanu had little doubt that additional information would only confirm the observations to date. He knew nothing of the M-builders, still less of their psychology, but it struck him as profligate in the extreme to create two distinct kinds of thing which were all but identical in their major dimensions.

  No – he was sure of it: the moons were identical to the wheels. The wheels were down in the sea and the moons were in space, but they were the same class of object – simply assigned different functions.

  ‘How much of this,’ he asked, ‘is ringing a bell?’

  ‘All of it,’ Dakota said. ‘A moon always detached from its orbit and closed on us as we approached. The moons are the basic line of defence – the sentience filter. In a short while, it will sample us.’

  ‘Am I going to like that?’ Nissa asked.

  ‘It depends how you feel about terror.’

  The moon – or, more accurately, the wheel – continued its approach. Within minutes, its rate of spin had dropped to a few rotations a second. Then – with a surprising abruptness – it locked still, its central axis aligned with Icebreaker. It was closing at a rate that they could never have outrun, even with a fully functioning Chibesa core.

  Besides, Dakota was clear: it would have been perfectly futile to run. The moons allowed nothing to evade their scrutiny. If they veered from the reach of this one, the remaining moons would simply mesh their orbits tighter. And if by chance there had been some trajectory which allowed them to slip beyond the moons, Icebreaker would simply be destroyed with long-range weaponry as a precautionary measure.

  ‘They allowed us through once,’ Kanu said.

  ‘Your course was oblique to Poseidon. The moons determined that you had no intention of slowing or landing. Do not think of that as clemency – it isn’t. The moons simply determined that you were neither a threat nor of interest to them. They guard their energy carefully – nothing is without cost, even to the M-builders. But you still did very well to survive after your entanglement with the Watchkeeper. Be glad you never went deeper.’

  ‘I’d be glad if weren’t going deeper now,’ Nissa said.

  ‘For years – decades – I lived for this.’ But after a silence Dakota added: ‘Now I am not so sure.’

  They watched as a silver filament formed a cord between two parts of the moon’s inner arc. The filament lengthened until it spanned the diameter, like a single hubless spoke. They had seen nothing of how the filament was generated, or any suggestion of how it was sustained.

  ‘What is it?’ Kanu asked.

  ‘The means by which we shall be sampled,’ said Dakota. ‘It is a physical scanning process – a kind of examination by touch. But do not be alarmed. This is not the thing that will harm us.’

  The moon had begun to rotate again, but now the axis of rotation was at right angles to its previous orientation. The spin accelerated quickly, drawing the single silver spoke into a flat silver disc. The disc was slightly translucent, stars and planets still visible through it. Now the wheel began to gain on Icebreaker until the silver surface was only a few hundred metres aft of the vessel.

  ‘The first time,’ Dakota said, ‘we thought this must be a weapon. We believed we were going to die. In hindsight, though, it would have made a very clumsy tool of execution. We should have understood that it was a learning machine, not a weapon.’

  Kanu studied the bridge display. The schematic outline of the ship showed a sketchy, barely apprehended surface closing in from behind, like a fog bank.

  ‘What will happen when it touches us? Will it pass through the hull?’

  ‘The sampling surface will not be interrupted. It will pass through every system of Icebreaker – including the Chibesa core.’

  ‘And us?’

  ‘From the perspective of the M-builders, we are all just systems of the ship.’

  The silver wall had begun to consume the ship from the tail end. But there were no emergency warnings, no sense of any damage or impairment to the propulsion systems beyond that which they had already sustained. Icebreaker was aware of the surface passing around it but had no perception of any more significant violation of its integrity.

  ‘I want to see this,’ Nissa said. ‘For real, with my own eyes.’

  ‘You will, soon enough.’

  ‘I mean while there’s time to compose some last thoughts. Will it matter if we move around?’

  ‘Nothing you think, say or do will make the slightest difference now,’ Dakota assured her. ‘This is the price of your forgiveness, in sparing us.’

  ‘Would you rather we hadn’t?’

  ‘I suspect you will come to believe so.’

  ‘Such gratitude,’ Nissa said.

  ‘Oh, I am grateful. You had the means to escape and we were safely unconscious. You could hardly have been blamed had you put yourselves before the Risen. I still wonder why you did not. You had everything to gain, and now you have nothing.’

  ‘But I can still look myself in the eye in a mirror,’ Kanu said.

  He followed Nissa. Instead of going directly to the central shaft, she stopped at the spacesuit locker and began donning layers as quickly as she could. For a moment Kanu merely watched, wondering how she thought a spacesuit was going to help her when the silver surface arrived. But the impulse to do something was inarguable, as human as the reflex to raise a hand against a striking knife. He began to put on his own spacesuit, skipping the usual safety checks for the sake of urgency.

  ‘I know this won’t make much difference,’ Nissa said, ‘but if the ship breaks up around us, I don’t want to die with vacuum in my lungs. I’ll take oxygen starvation over decompression any time.’

  ‘I’ve never been keen on drowning,’ Kanu confessed. ‘I ima
gine the two scenarios aren’t all that different.’

  They left their helmets off for now, judging that there would be time to put them on if the ship really did begin to suffer some catastrophic structural failure. With the helmets tucked under their arms, they continued further into the ship. They did not have far to go before they reached the end of the central shaft, which ran a significant part of the distance back to the propulsion section. The shaft stretched away before them, picked out by running lights.

  They floated there, holding gloved hands. Neither of them needed to say anything. They could see what was coming.

  The end of the shaft was a moving silver surface. It filled the shaft perfectly, as smooth and tight-fitting as a plug of liquid mercury. It was slightly mirrored, so they were able to see the converging perspective lines of the shaft. Far in the distance, where those perspective lines pinched together, lay their own tiny reflections – two floating suited forms, barely distinguishable from each other.

  ‘The ship is still there, beyond the surface,’ Swift said. ‘We would know by now if that were not the case. It is not a destructive sampling process. The material must be examining matter on the molecular level, then reconsitituting it as it passes through.’

  ‘Shut up, Swift,’ Nissa said. ‘I need to face this without you in my head.’

  Kanu squeezed her hand. ‘It’ll be all right.’

  His instincts told him to try to paddle away from the approaching surface, but he could never have made enough speed to outpace it. Besides, there was nowhere to go. At least this way they would face it with dignity.

  It came fast, appearing to accelerate as it consumed the last few metres of the shaft, but that must have been an optical illusion. Kanu stiffened his body and held his breath – it was impossible not to, even as his rational mind argued that it would make no difference. Nissa’s grip tightened on his own.