A mile below the lowest cloud, rock breaches water and the sea begins.

It has been given many names. Each inlet and bay and stream has been classified as if it were discrete. But it is one thing, where borders are absurd. It fills the spaces between stones and sand, curling around coastlines and filling trenches between the continents.

At the edges of the world the salt water is cold enough to burn. Huge slabs of frozen sea mimic the land, and break and crash and reform, crisscrossed with tunnels, the homes of frost-crabs, philosophers with shells of living ice. In the southern shallows there are forests of pipe-worms and kelp and predatory corals. Sunfish move with idiot grace. Trilobites make nests in bones and dissolving iron.

The sea throngs.

There are free-floating top-dwellers that live and die in surf without ever seeing dirt beneath them. Complex ecosystems flourish in neritic pools and flatlands, sliding on organic scree to the edge of rock shelves and dropping into a zone below light.

There are ravines. Presences something between molluscs and deities squat patiently below eight miles of water. In the lightless cold a brutality of evolution obtains. Rude creatures emit slime and phosphorescence and move with flickerings of unclear limbs. The logic of their forms derives from nightmares.

There are bottomless shafts of water. There are places where the granite and muck base of the sea falls away in vertical tunnels that plumb miles, spilling into other planes, under pressure so great that the water flows sluggish and thick. It spurts through the pores of reality, seeping back in dangerous washes, leaving fissures through which displaced forces can emerge.

In the chill middle deeps, hydrothermic vents break through the rocks and spew clouds of superheated water. Intricate creatures bask in this ambient warmth their whole short lives, never straying beyond a few feet of warm, mineral-rich water into a cold which would kill them.

The landscape below the surface is one of mountains and canyons and forests, shifting dunes, ice caverns and graveyards. The water is dense with matter. Islands float impossibly in the deeps, caught on charmed tides. Some are the size of coffins, little slivers of flint and granite that refuse to sink. Others are gnarled rocks half a mile long, suspended thousands of feet down, moving on slow, arcane streams. There are communities on these unsinking lands: there are hidden kingdoms.

There is heroism and brute warfare on the ocean floor, unnoticed by land-dwellers. There are gods and catastrophes.

Intruding vessels pass between the sea and the air. Their shadows fleck the bottom where it is high enough for light to reach. The trading ships and cogs, the whaling boats pass over the rot of other craft. Sailors’ bodies fertilize the water. Scavenger fish feed on eyes and lips. There are jags in the coral architecture where masts and anchors have been reclaimed. Lost ships are mourned or forgotten, and the living floor of the sea takes them and hides them with barnacles, gives them as caves to morays and ratfish and cray outcastes; and other more savage things.

In the deepest places, where physical norms collapse under the crushing water, bodies still fall softly through the dark, days after their vessels have capsized.

They decay on their long journey down. Nothing will hit the black sand at the bottom of the world but algae-covered bones.

At the edges of the shelves of rock where cold, light water gives way to a creeping darkness, a he-cray scrambles. He sees prey, clicks and rattles deep in his throat while he slips the hood from his hunting squid and releases it.

It bolts from him, diving for the shoal of fat mackerel that boil and re-form like a cloud twenty feet above. Its foot-long tentacles open and whip closed again. The squid returns to its master, dragging a dying fish, and the school reknits behind it.

The cray slices the head and tail from the mackerel and slips the carcass into a net bag at his belt. The bloody head he gives his squid to gnaw.

The upper body of the cray, the soft, unarmored section, is sensitive to minute shifts of tide and temperature. He feels a prickling against his sallow skin as complex washes of water meet and interact. With an abrupt spasm the mackerel-cloud congeals and disappears over the crusted reef.

The cray raises his arm and calls his squid closer to him, soothes it gently. He fingers his harpoon.

He is standing on a granite ridge, where seaweed and ferns move against him, caressing his long underbelly. To his right, swells of porous stone rise above him. To the left the slope falls away fast into disphotic water. He can feel the chill emanating from below. He looks out into a steep gradation of blue. Way overhead, on the surface, there are ripples of light. Below him the rays peter swiftly out. He stands only a little way above the border of perpetual dark.

He treads carefully here, on the edge of the plateau. He often comes to hunt here, where prey are less careful, away from the lighter, warmer shallows. Sometimes big game rises curiously from the pitch, unused to his shrewd tactics and barbed spears. The cray shifts nervously in the current and stares out into the open sea. Sometimes it is not prey but predators that rise from the twilight zone.

Eddies of cold roll over him. Pebbles are dislodged around his feet and bounce slowly down the slope and out of sight. The cray braces himself on the slippery boulders.

Somewhere below him there is a soft percussion of rocks. A chill not carried by any current creeps across his skin. Stones are realigning, and a spill of thaumaturgic wash is spewing through new crevices.

Something baleful is emerging in the cold water, at the edge of the dark.

The cray hunter’s squid is beginning to panic, and when he releases it again, it jets instantly up the slope, toward the light. He peers back into the murk, looking for the source of the sound.

There is an ominous vibration. As he tries to see through water stained by dust and plankton, something moves. Way below, a plug of rock bigger than a man shudders. The cray bites his lip as the great irregular stone falls suddenly free and begins a grinding descent.

The thundering of its passage reverberates long after it has become invisible.

There is a pit in the slope now, that stains the sea with darkness. It is quiet and motionless for a time, and the cray fingers his spear with anxiety, clutching at it and hefting it and feeling himself tremble.

And then, softly, something colorless and cold slips from the hole.

It confuses the eye, flitting with a grotesque organic swiftness that seems to belie intention, like gore falling from a wound. The he-cray is quite still. His fear is intense.

Another shape emerges. Again he cannot make it out: it evades him; it is like a memory or an impression; it will not be specified. It is fast and corporeal and coldly terrifying.

There is another, and then more, until a constant quick stream dribbles from the darkness. The presences shift, not quite invisible, communing and dissipating, their movements opaque.

The he-cray is still. He can hear strange, whispering discourses on the tides.

His eyes widen as he glimpses massive backbent teeth, bodies pebbled with rucks. Sinuous muscled things fluttering in the freezing water.

The he-cray starts and steps backward, his feet skittering on sloping stone, trying to quiet himself but too slow-small shattered sounds emerging from him.

With a single motion, a lazy, predatory twitch, the dark things that huddle in council below him move. The he-cray sees the darks of a score of eyes, and he knows with a sick-making fear that they are watching.

And then with a monstrous grace, they rise, and are upon him.

Chapter Thirteen

Silas and Bellis spent two nights together.

During the days, Bellis shelved, helped Shekel to read and told him about Croom Park, sometimes ate with Carrianne. Then she returned to Silas. They talked some, but he left her quite ignorant of how he passed his hours. She had a sense that he was full of secret ideas. They fucked several times.

After the second night, Silas disappeared. Bellis was glad. She had been neglecting Johannes’ books, and she now returned to their unfamiliar science.

Silas was gone for three days.

Bellis explored.

She ventured finally into the farthest parts of the city. She saw the burn temples of Bask riding, and its triptych statues spread across the fabric of several boats. In Thee-And-Thine (which was not as rough or as frightening as she had been led to believe, was little more than an exaggerated, pugnacious marketplace) she saw the Armada asylum, a massive edifice that loomed from a steamer, cruelly placed, it seemed to Bellis, right next to the haunted quarter.

There was a little outcropping of Garwater boats like a buffer between Curhouse and Bask, separated off from the main body of their riding by some historical caprice. There, Bellis found the Lyceum, its workshops and classrooms staggering precipitously down the sides of a ship, layered like a mountainside town.

Armada had all the institutions of any city on land, devoted to learning and politics and religion, only perhaps in a harder form. And if the city’s scholars were tougher than their landside equivalents, and looked more like rogues and pirates than doctors, it did not invalidate their expertise. There were different constabularies in each riding, from the uniformed proctors of Bask to Garwater’s loosely defined yeomanry who were marked out only by their sashes-a badge as much of loyalty as office. Each riding’s law was different. There was a species of court and disputation in Curhouse, while the lax, violent, piratical discipline of Garwater was doled out with the whip.

Armada was a profane and secular city, and its unkempt churches were treated as irreverently as its bakers. There were temples to the deified Croom; to the moon and her daughters, to thank them for the tides; to sea gods.

If she ever became lost, Bellis needed only to find her way out from backstreets or alleys, look up through all the aerostats moored to masts, and find the Arrogance, looming stately over the glowering Grand Easterly. It was her beacon, and by it she steered her way home.

In the midst of the city there were rafts-wooden floats extending scores of yards to each side. Houses perched ludicrously on them. There were needle-thin submarines bobbing tethered between barquentines, and chariot ships filled with hotchi burrows. Tumbledown buildings smothered decks or perched precarious across the backs of tens of tiny vessels in the cheap neighborhoods. There were playhouses and prisons and deserted hulks.

When she raised her eyes to the horizon, Bellis could see disturbances out to sea: churning water, wakes without obvious cause. Wind- and weather-born, usually, but sometimes she might glimpse a pod of porpoises, or a plesiaur or seawyrm neck, or the back of something big and fast that she could not identify. The life beyond the city, and all around it.

Bellis watched the city’s fishing boats return in the evenings. Sometimes pirate ships would appear and be welcomed back into the harbors of Basilio or Urchinspine, the motors of Armada’s economy finding their way, uncannily, home.

Armada was full of figureheads. They poked up in unlikely places, ornate and ignored like the carved door knockers on New Crobuzon houses. At the end of a terrace, walking between rows of close brick dwellings, Bellis might come face-to-face with a splendid corroded woman, her breastplate moldering, her painted gaze flaked and vague. Hanging in the air like a spirit, below the bowsprit of her ship, which jutted across its neighbor’s deck and pointed into the alley.

They were all around. Otters, drakows, fish, warriors, and women. Above all women. Bellis hated the blank-eyed, curvaceous figures, wobbling up and down moronically with the swell, haunting the city like banal ghosts.

In her room, she finished Essays on Beasts and remained uncomprehending of Armada’s secret project.

She wondered where Silas was, and what he was doing. She was not upset or angry at his absence, but she was curious and a little frustrated. He was, after all, the closest thing she had to an ally.

He returned on the evening of the fifth of Lunuary.

Bellis let him enter. She did not touch him, nor he her.

He was tired and subdued. His hair was mussed, his clothes dusty. He sat back in a chair and covered his hands with his eyes, murmuring something inaudible, some greeting. Bellis made him tea. She waited for him to speak, and when after a while he did not, she returned to her book and her cigarillo.

She had made several more pages of notes before he spoke.

“Bellis. Bellis.” He rubbed his eyes and looked up at her. “I have to tell you something. I have to tell you the truth. I’ve kept things from you.”

She nodded, turning to face him. His eyes were closed.

“Let’s… take stock,” he said slowly. “The city’s heading south. The Sorghum… Do you know what the Sorghum’s for? The Sorghum, and the other rigs that I gather the Terpsichoria took you past, suck fuel from under the sea.”

He spread his hands wide, indicating massiveness. “There are fields of oil and rockmilk and mercus under the earth, Bellis. You’ve seen the screwbores they use to plumb for the stuff on land. Well, geo-empaths and the like have found vast deposits under the rock, lying under the sea.

“There’s oil under southern Salkrikaltor. That’s why the Manikin and the Trashstar and Sorghum have been perched out there for more than three decades. The supports of the Manikin and Trashstar go down four hundred feet and sit on the bottom. But the Sorghum… The Sorghum’s different.” He spoke with a morbid relish. “Someone in Armada knew what they were doing, I tell you. The Sorghum sits on two iron hulls-submersibles. The Sorghum’s not tethered. The Sorghum’s a deepwater rig. The Sorghum can travel.

“You can just keep adding sections to its drill shaft, and it can go down Jabber fucking knows how far. Miles down. You can’t find oil and so on everywhere. That’s why we were stationary for so long. Armada was sitting over a field of something or other the Sorghum could get at, and we couldn’t move off until it had stored up for wherever it’s going.”

How do you know all this? thought Bellis. What’s this truth you have to tell me?

“I don’t think it’s just oil,” Silas continued. “I’ve been watching the flame over the rig, Bellis. I think they’ve been drawing up rockmilk.”

Rockmilk. Lactus saxi. Viscous and heavy as magma, but bone cold. And dense with thaumaturgons, the charged particles. Worth several times its considerable weight in gold, or diamonds, or oil or blood.

“Ships don’t use fucking rockmilk to fire their engines,” Silas said. “Whatever they’ve stockpiled for, it’s not just to keep their vessels trim. Look at what’s happening. We’re heading south, to deeper, warmer seas. I’ll bet you a finial we’re skirting close to ridges beneath, where there are deposits, a route that lets the Sorghum drill. And when we get wherever we’re going, your friend Johannes and his new employers are going to use… what, several tons of rockmilk and Jabber knows how much oil to do… something. By which time…” He paused, and held her gaze. “By which time it’ll be too late.”

Tell me, Bellis thought, and Silas was nodding as if he had heard her.

“When we met on the Terpsichoria, I was in something of a state, I remember. I told you I had to return to New Crobuzon immediately. You reminded me of that yourself, recently. And I told you that I’d been lying. But I wasn’t. What I said on Terpsichoria was true: I have to return. Dammit, you probably realized all this.”

Bellis said nothing.

“I didn’t know how to… I didn’t know if I could trust you, if you’d care,” he continued. “I’m sorry I wasn’t honest with you, but I didn’t know how far I could go. But dammit, Bellis, I trust you now. And I need your help.

“It’s true, what I told you, that sometimes the grindylow turn against some poor sod for no reason anyone can figure. That people disappear at their whim. The grindylows’ whim, the deeplings.” But it’s not true, what I said then, about that happening to me. I know exactly why the grindylow wanted to kill me.

“If they chose, the grindylow could swim upriver to the top of the Bezheks, where all the rivers join together, and they could cross into the Canker. Be swept downriver on the other side of the mountains, all the way to New Crobuzon.

“Others could cross into the ocean through the tunnels, come at the city by sea. They’re euryhalinic, the grindylow, happy in freshwater or brine. They could make their way to Iron Bay. To the Gross Tar, and New Crobuzon. All it would take for the grindylow to get to the city is determination. And I know they have that.”

Bellis had never seen Silas so tense.

“When I was there, there were rumors. Some big plan was in the offing. One of my clients, a magus, a kind of thug-priest, its name came up again and again. I started to keep my eyes and ears open. That’s why they want to kill me. I found something out.

“The grindylow don’t do secrecy; they don’t do policing as we do. There was evidence in front of me for weeks, but it took me a long time to recognize it. Mosaics, blueprints, librettos, and such-like. Took me a long time to understand.”

“Tell me what you found,” said Bellis.

“Plans,” he said. “Plans for an invasion.”

“It would be like nothing you can imagine,” he said. “Gods know our history’s littered with betrayal and fucking blood, but… ‘Stail, Bellis… You’ve never seen The Gengris.” There was a desperation in his voice that Bellis had never heard before. “You’ve never seen the limb-farms. The workshops, the fucking bile workshops. You’ve never heard the music.

“If the grindylow take New Crobuzon, they wouldn’t enslave us, or kill us, or even eat us all. They wouldn’t do anything so… comprehensible.”

“But why?” said Bellis, finally. “What do they want? Do you think they can do it?”

“I don’t godsdamned know. No one knows a thing about them. I suspect the New Crobuzon government has more plans about what to do if fucking Tesh invades than if the grindylow do. We’ve never had any reason to be scared of them. But they have their own… methods, their own sciences and thaumaturgies. Yes,” he said. “I think they have a chance.

“They want New Crobuzon for the same reason every other state or savage on Ragamoll does. It’s the richest, the biggest, the most powerful. Our industries, our resources, our militia-look at everything we have. But unlike Shankell or Dreer Samher or Neovadan or Yoraketche, The Gengris… The Gengris has a chance.

“They can come with surprise… Poison the water, come into the sewers. Every godsdamn crevice and crack and water tank in the city would be a fucking encampment. They can storm us with weapons we’d never understand, in an endless guerrilla war.

“I’ve seen what the grindylow can do, Bellis.” Silas sounded exhausted. “I’ve seen it, and I’m scared.”

From outside came the far-off sound of monkeys squabbling sleepily.

“That’s why you left,” said Bellis in the quiet that followed.

“That’s why I left. I couldn’t believe what I’d found out. But I dithered… I fucking farted time away.” His anger welled up suddenly. “And when I realized that there was no fucking mistake, that this wasn’t a confusion, that they really did intend to unleash some godsforsaken unthinkable apocalypse on my hometown… then I left. I stole the sub, and left.”

“Do they know that… you know?” she asked.

He shook his head. “I don’t think so,” he said. “I took some stuff with me, so that it looks like I stole and ran.”

Bellis could see that he was tight with tension. She could remember some of the heliotypes she had seen in his notebook. Her heart lurched, and slow alarm crept through her with her blood, like a sickness. Bellis struggled to grasp what he was telling her. It was too big for her; it made no sense. She could not contain it. New Crobuzon… How could it be threatened?

“Do you know how long?” she whispered.

“They have to wait till Chet to harvest their weapons,” he said. “So maybe six months. We have to find out what Armada’s planning to do, because we have to know where we’re going, with this fucking rockmilk and all. Because we… we have to get a message back to New Crobuzon.”

“Why,” Bellis breathed, “didn’t you tell me before?”

Silas laughed hollowly. “I didn’t know who on this place to trust. I was trying to get away from here myself, trying to find some way home. It took me a long time to believe that… that there wasn’t any. I thought I could just take the message to New Crobuzon myself. What if you didn’t believe me? Or what if you were a spy? What if you told our new fucking rulers-”

“Well, what about that?” Bellis interrupted. “Isn’t it worth thinking about? Maybe they’d help us get a message…”

Silas stared at her with nasty incredulity.

“Are you mad?” he said. “You think they’d help us? They don’t give spit what happens to New Crobuzon. They’d most likely welcome its fucking destruction-one less competitor nation on the sea. You think they’d let us ride to the rescue? You think they’d care? The bastards would probably do everything they could to hold us back, to let the grindylow do their worst. And, besides, you’ve seen how they treat… Crobuzoner officials and agents. They’d search my notes, my papers, and it would come out that I have a commission. That I work for New Crobuzon. Jabber Almighty, Bellis, you saw what they did to the captain. What do you think they’d do to me?”

There was a long silence at that.

“I needed… I need someone to work with me. We have no friends in this city. We have no allies. And thousands of miles away, our home’s in danger, and we can’t trust anyone to help us. So it’s up to us to get a message back.”

After he said that there was a pause that became a silence. It dragged out, longer and longer, and became terrible because they both knew it should be filled. They should be coming up with plans.

And both of them tried. Bellis opened her mouth several times, but words dried in her throat.

We’ll hijack one of their boats, she wanted to say but could not; the idiocy of it choked her. We’ll sneak out just the two of us in a dinghy; we’ll get through the guard boats and row and sail for home. She tried to say that, tried to think it without scorn, and almost moaned. We’ll steal an airship. All we need are guns and gas, and coal and water for the engine, and food and drink for a two-thousand-mile journey, and a map, a chart of where in the godsforsaken fucking middle of the fucking entire Swollen Ocean we are, for Jabber’s sake…

Nothing, there was nothing, she could say nothing; she could think nothing.

She sat and tried to speak, tried to think of ways she could save New Crobuzon, her city which she treasured with a ferocious, unromantic love, and which lay under the most baleful threat. And the moments passed and passed, and Chet and the summer and the grindylow harvest kept coming closer, and she could say nothing.

Bellis imagined bodies like puffy eels, eyes and slablike recurved teeth heading under cold water toward her home.

“Oh dear gods, dear Jabber…” she heard herself say. She met Silas’ troubled eyes. “Dear gods, what are we going to do?”