Part Two
"There are definitely tunnels here," Sayaca said, years later.
Their cutter was parked on an airless plain near Cinder's equator, squatting down on skids like a beached black fish. Bright Boy was almost overhead; a disk of fierce radiance casting razor-edged shadows like pools of ink. Merlin moved over to Sayaca's side of the cabin to see the data she was projecting before her, sketched in ruddy contours. Smelling her, he wanted to bury his face in her hair and turn her face to his before kissing her, but the moment was not right for that. It had not been right for some time.
"Caves, you mean?" Merlin said.
"No; tunnels." She almost managed to hide her irritation. "Like I always said they were. Deliberately excavated. Now do you believe me?"
There had been hints of them before, from orbit, during the first months after the arrival around the star. Starling had sent expeditionary teams out to a dozen promising niches in the system, tasking them to assess the benefits of each before a final decision was made. Most of the effort was focussed around Cinder and Ghost—they had even put space stations into orbit around the gas giant—but there were teams exploring smaller bodies, even comets and asteroids. Nothing would be dismissed without at least a preliminary study. There were even teams working on fringe ideas like hiding inside the sun's chromosphere.
And for all that, Merlin thought, they still won't allow me near the other syrinx.
But at least Cinder was a kind of distraction. Mapping satellites had been dropped into orbits around all the major bodies in the system, measuring the gravitational fields of each body. The data, unraveled into a density-map, hinted at a puzzling structure within Cinder—a deep network of tunnels riddling the lithosphere. Now they had even better maps, constructed from seismic data. One or two small asteroids hit Cinder every month. With no atmosphere to slow them down, they slammed into the surface at many kilometers per second. The sound waves from those impacts would radiate through the underlying rock, bent into complex wave fronts as they traversed density zones. They would eventually reach the surface again, thousands of kilometers away, but the precise pattern of arrival times—picked up across a network of listening devices studding the surface—would depend on the route that the sound waves had taken.
Now Merlin could see that the tunnels were definitely artificial. "Who do you think dug them?"
"From here, there's no way we'll ever know." Sayaca frowned, puzzling over something in her data, and then seemed to drop the annoyance, at least for now, rather than have it spoil her moment of triumph. "Whoever it was, they tidied up after themselves. We'll have to go down—get into them."
"Perhaps we'll find somewhere to hide."
"Or find someone else already hiding." Sayaca looked into his face, her expression one of complete seriousness.
"Maybe they'll let us hide with them." She turned back to her work. "Or maybe they'd rather we left them alone."
Several months later Merlin buckled on an immersion suit, feeling the slight prickling sensation around the nape of the neck as the suit hijacked his spinal nerves. Vision and balance flickered—there was a perceptual jolt he never quite got used to—and then suddenly he was back in the simulated realm of the Palace. He had to admit it was good; much better than the last time he had sampled Gallinule's toy environment.
"You've been busy," he said.
Gallinule's image smiled. "It'll do for now. Just wait till you've seen the sunset wing."
Gallinule led him through the maze of high-ceilinged, baroquely walled corridors that led from the oubliette to the other side of the Palace. They ascended and descended spiral staircases and crossed vertiginous inner chambers spanned by elegantly arched stonework bridges, delicate subtleties of masonry highlighted in sunset fire. The real Palace of Eternal Dusk had been ruined along with every other sign of civilization when the Huskers had torched Plenitude. This simulation was running in the main encampment inside Cinder, but Gallinule had spread copies of it around the system, wherever he might need a convenient venue for discussion.
"See anything that looks out of place?" Gallinule said.
Merlin looked around, but there was nothing that did not accord with his own memories. Hardly surprising. Of the two of them, Gallinule had always been the one with the eye for detail.
"It's pretty damned good. But why? And how?"
"As a test-bed. Aboard Starthroat, we never needed good simulation techniques. But our lives depend upon making the right choices around Bright Boy. That means we have to be able to simulate any hypothetical situation and experience it as if it were totally real."
Merlin agreed. The discovery that the tunnels in Cinder were artificial had enormously complicated the hideaway project. They had been excavated by a hypothetical human splinter group, which Sayaca had dubbed the Diggers. No one knew much about them. Certainly they had been more advanced than any part of the Cohort, but while their machines—lining the tunnels like a thick arterial plaque—seemed unfathomably strange, they were not quite strange enough to suggest that they had been installed by the Waymakers. And they were quite clearly human: markings were in a language that the linguists said had ancient links to Main. The Diggers were simply one of the thousands of cultures that had ascended to heights of technical prowess without making any recognizable dent on human history.
" . . . anyway, who knows what nasty traps the Diggers left us,"Gallinule was saying. "With simulations, we'll at least be able to prepare for the more obvious surprises." His youthful image shrugged. "So I initiated a crash program to resurrect the old techniques. At the moment we have to wear suits to achieve this level of immersion, but in a year or so we'll be able to step into simulated environments as easily as walking from one room to another."
They had reached a balcony on the sunset side of the Palace of Eternal Dusk. He leaned over the balustrade as far as he dared, seeing how the lower levels of the Palace dropped away toward the rushing sea below. The Palace of Eternal Dusk circled Plenitude's equator once a day, traveling with the line that divided day from night. Its motion caused Plenitude's sun to hang at the same point in the sky, two-thirds of its swollen disk already consumed by the sea. Somewhere deep in the keel of rock which the Palace rode lay throbbing mechanisms that both sustained the structure's flight—it had been flying for longer than anyone remembered—and generated the protective bubble that held it in a pocket of still air, despite its supersonic velocity relative to the ground.
Merlin's family had held the Palace for thirteen hundred years, after a short Dark Age on Plenitude. The family had been among the first to rediscover powered flight, using fragile aircraft to reach the keel. Other contenders had come, but the family had retained their treasure across forty generations, through another two Dark Ages.
Finally, however, the greater war had touched them.
A damaged Cohort swallowship had been the first to arrive, years ahead of a Husker swarm. The reality of interstellar travel was still dimly remembered on Plenitude, but those first newcomers were still treated with suspicion and paranoia. Only Merlin's family had given them the benefit of the doubt . . . and even then, not fully heeded the warning when it was given. Against their ruling mother's wishes, the two brothers had allowed themselves to be taken aboard the swallowship and inducted into the ways of the Cohort. Their old names were discarded in favor of new ones, in the custom of the swallowship's crew. They learned fluency in Main.
After several months, Merlin and Gallinule had been preparing to return home as envoys. Their plan was simple enough. They would persuade their mother that Plenitude was doomed. That would not be the easiest of tasks, but their mother's co-operation was vital if anything was to be saved. It would mean establishing peace among the planet's various factions, where none had existed for generations. There were spaces in the swallowship's frostwatch holds for sleepers, but only a few hundred thousand, which would mean that each region must select its best. It would not be easy, but there were still years in which to do it. "None of it will make any difference," their mother had said. "No one will listen to us, even if we believe everything Quail says."
"They have to."
"Don't you understand?" she said. "You think of me as your mother, but to fifty million of Plenitude's inhabitants I'm a tyrant."
"They'll understand," Merlin said, half-believing it himself.
But then the unthinkable had happened. A smaller element of the swarm had crept up much closer than anyone had feared, detected only when it was already within Plenitude's system. The swallowship's captain made the only decision he could, which was to break orbit immediately and run for interstellar space.
Merlin and Gallinule fought—pleaded—but Quail would not allow them to leave the ship. They told him all they wanted was to return home. If that meant dying with everyone else on Plenitude, including their mother, so be it.
Quail listened, and sympathized, and still refused them. It was not just their genes that the Cohort required, he said. Everything else about them: Their stories. Their hopes and fears. The tiniest piece of knowledge they carried, considered trivial by them, might prove to be shatteringly valuable. It was many decades of shiptime since they had found another pocket of humanity. Merlin and Gallinule were simply too precious to throw away.
Even if it meant denying them the right to die with valor.
Instead, on Starthroat's long-range cameras, relayed from monitoring satellites sown around Plenitude, they watched the Palace of Eternal Dusk die, wounded by weapons it had never known before, stabbing deep into the keel on which it flew, destroying the engines that held it aloft. It came down slowly, grinding into the planetary crust, gouging a terrible scar across half of one scorched continent before it came to rest, ruined and lop-sided.
And now Gallinule had made this.
"If you can do all this now . . . " Merlin mused. He left the remark hanging, knowing his brother would take the bait.
"As I said, full immersion in a year or so. Then we'll need better methods to deal with the time-lag for communications around Bright Boy. We can't even broadcast signals for fear of them being intercepted by the Huskers, which limits us to line-of-sight comms between relay nodes sprinkled around the system. Sometimes the routing will add significant delays. That's why we need another kind of simulation. If we can create semblances—"
Merlin stopped him. "Semblances?"
"Sorry. Old term I dug from the troves. Another technique we've forgotten aboard Starthroat. We need to be able to make convincing simulacra of ourselves, with realistic responses across a range of likely stimuli. Then we can be in two places at once—or as many as we want to be. Afterward, you merge the memories gathered by your semblances."
Merlin thought about that. Many cultures known to the Cohort had developed the kind of technology Gallinule was referring to, so the concept was not unfamiliar to him.
"These wouldn't be conscious entities, though?"
"No; that's far down the line. Semblances would just be mimetic software: clever caricatures. Of course, they'd seem real if they were working well. Later . . . "
"You'd think of adding consciousness?"
Gallinule looked around warily. It was a reflex, of course—there could not possibly have been eavesdroppers in this environment he had fashioned—but it was telling all the same. "It would be useful. If we could copy ourselves entirely into simulation—not just mimesis, but neuron-by-neuron mapping— it would make hiding from the Huskers very much easier."
"Become disembodied programs, you mean? Sorry, but that's a definite case of the cure being worse than the disease."
"Eventually it won't seem anywhere near as chilling as it does now. Especially when our other options for hiding look less and less viable."
Merlin nodded sagely. "And you'd no doubt do all in your power to make them seem that way, wouldn't you?"
Gallinule shrugged. "If Cinder's tunnels turn out to be the best place to hide, so be it. But it's senseless not to explore other options." Merlin watched the way his knuckle tightened on the stone balustrade, betraying the tension he tried to keep from his voice.
"If you make an issue of this," Merlin said carefully, "you'd better assume I'll fight you, brother or not."
Gallinule touched Merlin's shoulder. "It won't come to a confrontation. By the time the options are in, the correct path will be clear to us all . . . you included."
"The correct path's already clear to me. And it doesn't involve becoming patterns inside a machine."
"You'd prefer suicide instead?"
"Of course not. I'm talking about something infinitely better than hiding." He looked hard into his brother's face. "You have more influence on the Council than I do. You could persuade them to let me examine the syrinx."
"Why not ask Sayaca the same thing?"
"You know well why not. Things aren't the same between us these days. If you . . . oh, what's the point." Merlin removed Gallinule's hand from his shoulder. "Nothing that happens here will make the slightest difference to your plans."
"Spare me the self-righteousness, Merlin. It's not as though you're any different." Then he sighed, looking out to sea. "I'll demonstrate my commitment to the cause, if that's what you want. You know that Pauraque's still exploring the possibility of establishing a camouflaged base inside Ghost's atmosphere?"
"Of course."
"What you probably don't know is our automated drones don't work well at those depths. So we're going in with an exploration team next month. It'll be dangerous, but we have the Council's say-so. We know there's something down there, something we don't understand. We have to find out what it is."
Merlin had heard nothing about anything unexpected inside Ghost, but he feigned knowledge all the same.
"Why are you telling me this?"
"Because I'm accompanying Pauraque. We've equipped a two-person cutter for the expedition, armored to take thousands of atmospheres of pressure." Gallinule paused and clicked his fingers out to sea, making the blueprints of the ship loom large in the sky, sharp against the dark blue zenith. The blueprint rotated dizzyingly. "It's nothing too technical. Another ship could be adapted before we go down there. I'd be happy to disclose the mods."
Merlin studied the schematic, committing the salient points to memory. "This is a goad, isn't it?"
"Call it what you will. I'm just saying that my commitment to the greater cause shouldn't be in any doubt." Another finger click and the phantom ship vanished from the sky. "Where yours fits in is another thing entirely."
Part Three
For days Ghost had loomed ahead: a fat sphere banded by delicate equatorial clouds, encircled by moons and rings. Now it swallowed half the sky, cloud decks reaching up toward him; castellations of cream and ochre stacked hundreds of kilometers high. His approach was queried by the orbiting stations, but they must have known what the purpose of his visit was. His brother and Pauraque were already down there in the clouds. He had a faint fix on their ship as it steered itself into the depths.
The seniors around Cinder had been eager to get him out of their hair, so it had not taken much to persuade them to give him a ship of his own. He had customized it according to Gallinule's specifications and added a few cautious refinements of his own . . . and then named it Tyrant.
The hull creaked and sang as it reshaped itself for transatmospheric travel. The navigational fix grew stronger. With Merlin inside, the ship fell, knifing down through cloud layers. The planet had no sharply defined surface, but there came a point where the atmospheric pressure was exactly equivalent to the air pressure inside Tyrant. Below that datum, pressure and temperature climbed steadily. Gravity was an uncomfortable two gees, more or less tolerable if he remained in his seat.
The metasapphire hull creaked again, reshaping itself. Merlin had descended more than a hundred kilometers below the one-atmosphere datum, and the pressure outside was now ten times higher. Above fifty atmospheres, the hull would rely on internal power sources to prevent itself buckling. Merlin did his best not to think about the pressure, but there was no ignoring the way the light outside had dimmed, veiled by the masses of atmosphere suspended above his head. Down below it was oppressively dark, like the sooty heart of a thunderstorm wrapped around half his vision. Only now and then was there a stammer of lightning, which briefly lit the cathedrals of cloud below for hundreds of kilometers, down to vertiginous depths.
If there'd been more time, he thought, we'd have come with submarines, not spacecraft . . .
It was a dismal place to even think about spending any time in. But in that respect it made perfect sense. The thick atmosphere would make it easy to hide a modestly sized floating base, smothering infrared emissions. They would probably have to sleep during the hideaway period, but that was no great hardship. Better than spending decades awake, always knowing that beyond the walls was that crushing force constantly trying to squash you out of existence.
But there was something down here, Gallinule had said. Something that might count against using Ghost as a hideaway.
They had to know what it was.
"Warning," said Tyrant. "External pressure now thirty bars. Probability of hull collapse in five minutes is now five percent."
Merlin killed the warning system. It did not know about the augmentations he had made to the hull armoring, but it was still unnerving. Yet Pauraque and Gallinule were lower yet, and their navigational transponder was still working.
If they were daring him to go deeper, he would accept.
"Merlin?" said his brother's voice, trebly with echoes from the atmospheric interference. "So you decided to join us after all. Did you bring Sayaca with you?"
"I'm alone. I didn't see any point in endangering two of us."
"Shame. Well, I hope you implemented those hull mods, or this is going to be a brief conversation."
"Just tell me what it is we're expecting to see down here. You mentioned something unexpected."
Pauraque's voice now. "There's a periodic pressure phenomenon moving through the atmosphere, like a very fast storm. What it is, we don't know. Until we understand it, we can't be certain that hiding inside Ghost will work."
Merlin nodded, suddenly seeing Gallinule's angle. His brother would want the phenomenon to prove hazardous just so that his plan could triumph over Pauraque's. It was an odd attitude, especially as Pauraque and Gallinule were now said to be lovers, but it was nothing unusual as far as his brother was concerned.
"I take it you have a rough idea when we can expect to see this thing?"
"Reasonably good," Pauraque said. "Approach us and follow our vector. We're going deeper, so watch those integrity readings."
As if to underline her words, the hull chose that moment to creak—a dozen alerts sounding. Merlin grimaced, silencing the alarms, and gunned Tyrant toward the other ship.
Ghost was a classical gas giant, three hundred times more massive than Cinder. Most of the planet was hydrogen in its metallic state, overlaid by a deep ocean of merely liquid hydrogen. The cloud layers, which seemed so immense—and which gave the world its subtle bands of color—were compressed into only a few hundred kilometers of depth. Less than a hundredth of the planet's radius, yet those frigid, layered clouds of ammonia, hydrogen, and water were as deep as humans could go. Pauraque wanted to hide at the lowest layer above the transition zone where the atmosphere thickened into a liquid hydrogen sea, under a crystal veil of ammonium hydro-sulfide and water-ice.
Ahead now, he could see the glint of the other ship's thrusters, illuminating sullen cloud formations as it passed through them. Only a few kilometers ahead.
"You mentioned that the phenomenon was periodic,"Merlin said. "What exactly did you mean by that?"
"Exactly what I said," came Pauraque's reply, much clearer now. "The pressure wave—or focus—moves around Ghost once every three hours."
"That's much faster than any cyclone."
"Yes." The icy distaste in Pauraque's voice was obvious. She did not enjoy having a civil conversation with him. "Which is why we consider the phenomenon sufficiently—"
"It could be in orbit."
"What?"
Merlin checked the hull readouts again, watching as pressure hotspots flowed liquidly from point to point. Rendered in subtle colors, they looked like diffraction patterns on the scales of a sleek, tropical fish.
"I said it could be in orbit. If one of Ghost's moons was in orbit just above the top of the cloud layer, three hours is how long it would take to go around. The time would only be slightly less for a moon orbiting just below the cloud layer, where we are."
"Now you've really lost it," Gallinule said. "In orbit? Inside a planet?"
Merlin shrugged. He had thought about this already and had a ready answer, but he preferred that Gallinule believed him to be thinking the problem through even as they spoke. "Of course, I don't really think there's a moon down there. But there could still be something orbiting."
"Such as?" Pauraque said.
"A black hole, for instance. A small one—say a tenth of the mass of Cinder, with a light-trapping radius of about a millimeter. We'd have missed that kind of perturbation to Ghost's gravitational field until now. It wouldn't feel the atmosphere at all, not on the kind of timescales we're concerned with. But as the hole passed, the atmosphere would be tugged toward it for hundreds of kilometers along its track. Any chance that's your anomaly?"
There was a grudging silence before Pauraque answered. "I admit that at the very least it's possible. We more or less arrived at the same conclusion. Who knows how such a thing ended up inside Ghost, but it could have happened."
"Maybe someone put it there deliberately."
"We'll know soon enough. The storm's due any moment now."
She was right. The storm focus—whatever it was—moved at forty kilometers per second relative to Ghost's core, but since Ghost's equatorial cloud-layers were already rotating at a quarter of that speed, and in the same sense as the focus, the storm only moved at thirty kilometers per second against the atmosphere. Which, Merlin thought, was still adequately fast.
He told the cabin windows to amplify the available light, gathering photons from beyond the visible band and shifting them into the optical. Suddenly it was as if the overlaying veils had been stripped away; sunlight flooded the canyons and crevasses of cloud through which they were flying. The liquid hydrogen ocean began only a few tens of kilometers below them, under a transition zone where the atmospheric gases became steadily more fluidic. It was blood-hot down there; pressures nudged toward one hundred atmospheres. Not far below the sea they would climb into the thousands, at temperatures hot enough to melt machines.
And now something climbed above the horizon to the west. Tyrant began to shriek alarms, its dull machine-sentience comprehending that there was something very wrong nearby, and that it was a wrongness approaching at ferocious speed. The storm focus gathered clouds as it moved, tugging them violently out of formation. To Merlin's eyes, the way it moved reminded him of something from his childhood, something glimpsed moving through Plenitude's tropical waters with predatory swiftness: a darting mass of whirling tentacles.
"We're too high," Pauraque said. "I'm taking us lower. I want to be much closer to the focus when it arrives."
Before he could argue, Merlin saw the violet thrust spikes of the other ship. It slammed away, dwindling into the soupy stillness of the upper transition zone. He thought of a fish descending into some lightless ocean trench, into benthic darkness.
"Watch your shielding," he said, as he dove his own ship after them.
"Pressure's still within safe limits," Gallinule said, though they both knew that what now constituted safe was not quite the usual sense of the word. "I'll pull up if the rivets start popping, trust me."
"It's not just the pressure that worries me. If there's a black hole in that focus, there's also going to be a blast of gamma rays from the matter being sucked in."
"We haven't seen anything yet. Maybe the flux is masked by the clouds."
"You'd better hope it is."
Merlin was suited up, wearing the kind of high-pressure mobility armor he had only ever worn before in warcrèche simulations. The armor was prized technology, many kiloyears old; nothing like it now within the Cohort's technical reach. He hoped Gallinule and Pauraque were similarly prudent. If the hull gave in, the suits might only give them a few more minutes of life, but near something as unpredictable and chaotic as a miniature black hole, there was no such thing as too much shielding.
"Merlin?" Gallinule said. "We've lost a power node. Damn jury-rigged things. If there's a pressure wave before the focus we might start to buckle . . . "
"You can't risk it. Pull up and out. We can come back again on the next pass, three hours from now."
He had seen accretion disks, the swirls of matter around stellar-mass black holes and neutron stars, and what he saw near the storm's focus looked very similar: a spiraling concentration of cloud, tortured into rainbow colors as strange, transient chemistries came into play. They were so deep in the transition zone here that only tiny pressure changes were enough to condense the air into its fluid state. Lightning cartwheeled across the focus, driven by static differentials in the moving air masses. Merlin checked the range: close now, less than two hundred kilometers away.
And something was wrong.
Pauraque's ship was sinking too far, drifting too close to the heart of the storm. They were above it now, but their rate of descent would bring them close to the focus by the time it arrived.
"Force and wisdom; I told you to pull up, not go deeper!"
"We have a problem. Can't reshape the hull on our remaining nodes. No aerodynamic control." Gallinule's voice was calm, but Merlin knew his brother was terrified.
"Vector your thrust."
"Hell's teeth, what do you think I'm trying to do?"
No good. He watched the violet spikes of the other ship's thrusters stab in different directions, but there was nothing Gallinule could do to bring them out of their terminal descent. Merlin thought of the mods Gallinule had recommended. Unless he had added some hidden improvements, the other ship would implode in ten or fifteen seconds. There would be no surviving that.
"Listen to me," Merlin said. "You have to equalize pressure with the outside, or that hull's going to implode."
"We'll lose the ship that way."
"Don't argue, just do it! You have no more than ten seconds to save yourselves!"
He closed his eyes and hoped they were both suited. Or perhaps it would be better if they were not. To die by hull implosion would be swift, after all. The inrushing walls would move faster than any human nerve impulses.
On the magnified view of the other ship he saw a row of intakes flicker open along the dorsal line. Soup-thick atmosphere would have slammed in like an iron fist. Maybe their suits were good enough to withstand that shock.