He ups the gain on sonar, focusses aft. A luminous storm swirls across the tactical display. Beneath it, a fresh ridge of oozing rock disfigures the GA's construction grid.

Preteela is back at his elbow. "Joel?"

"Yeah."

"They say people are going to be living down there?"

"Uh huh."

"Wow. Who?"

He looks at her. "Haven't you seen the PR threads? Only the best and the brightest. Holding back the everlasting night to stoke the fires of civilization."

"Seriously, Joel. Who?"

He shrugs. "Fucked if I know."

When the lights go out in Beebe Station, you can hear the metal groan.

Lenie Clarke lies on her bunk, listening. Overhead, past pipes and wires and eggshell plating, three kilometers of black ocean try to crush her. She feels the Rift underneath, tearing open the seabed with strength enough to move a continent. She lies there in that fragile refuge and she hears Beebe's armor shifting by microns, hears its seams creak not quite below the threshold of human hearing. God is a sadist on the Juan de Fuca Rift, and His name is Physics.

How did they talk me into this? she wonders. Why did I come down here? But she already knows the answer.

She hears Ballard moving out in the corridor. Clarke envies Ballard. Ballard never screws up, always seems to have her life under control. She almost seems happy down here.

Clarke rolls off her bunk and fumbles for a switch. Her cubby floods with dismal light. Pipes and access panels crowd the wall beside her; aesthetics run a distant second to functionality when you're three thousand meters down. She turns and catches sight of a slick black amphibian in the bulkhead mirror.

It still happens, occasionally. She can sometimes forget what they've done to her.

It takes a conscious effort to feel the machines lurking where her left lung used to be. She's so acclimated to the chronic ache in her chest, to that subtle inertia of plastic and metal as she moves, that she's scarcely aware of them any more. She can still feel the memory of what it was to be fully human, and mistake that ghost for honest sensation.

Such respites never last. There are mirrors everywhere in Beebe; they're supposed to increase the apparent size of one's personal space. Sometimes Clarke shuts her eyes to hide from the reflections forever being thrown back at her. It doesn't help. She clenches her lids and feels the corneal caps beneath them, covering her eyes like smooth white cataracts.

She climbs out of her cubby and moves along the corridor to the lounge. Ballard is waiting there, dressed in a diveskin and the usual air of confidence.

Ballard stands up. "Ready to go?"

"You're in charge," Clarke says.

"Only on paper." Ballard smiles. "No pecking order down here, Lenie. As far as I'm concerned, we're equals." After two days on the rift Clarke is still surprised by the frequency with which Ballard smiles. Ballard smiles at the slightest provocation. It doesn't always seem real.

Something hits Beebe from the outside.

Ballard's smile falters. They hear it again; a wet, muffled thud through the station's titanium skin.

"It takes a while to get used to," Ballard says, "doesn't it?"

And again.

"I mean, that sounds big—"

"Maybe we should turn the lights off," Clarke suggests. She knows they won't. Beebe's exterior floodlights burn around the clock, an electric campfire pushing back the darkness. They can't see it from inside—Beebe has no windows— but somehow they draw comfort from the knowledge of that unseen fire—

Thud!

— most of the time.

"Remember back in training?" Ballard says over the sound, "When they told us that the fish were usually so—small…"

Her voice trails off. Beebe creaks slightly. They listen for a while. There's no other sound.

"It must've gotten tired," Ballard says. "You'd think they'd figure it out." She moves to the ladder and climbs downstairs.

Clarke follows her, a bit impatiently. There are sounds in Beebe that worry her far more than the futile attack of some misguided fish. Clarke can hear tired alloys negotiating surrender. She can feel the ocean looking for a way in. What if it finds one? The whole weight of the Pacific could drop down and turn her into jelly. Any time.

Better to face it outside, where she knows what's coming. All she can do in here is wait for it to happen.

Going outside is like drowning, once a day.

Clarke stands facing Ballard, diveskin sealed, in an airlock that barely holds both of them. She has learned to tolerate the forced proximity; the glassy armor on her eyes helps a bit. Fuse seals, check headlamp, test injector; the ritual takes her, step by reflexive step, to that horrible moment when she awakens the machines sleeping within her, and changes.

When she catches her breath, and loses it.

When a vacuum opens, somewhere in her chest, that swallows the air she holds. When her remaining lung shrivels in its cage, and her guts collapse; when myoelectric demons flood her sinuses and middle ears with isotonic saline. When every pocket of internal gas disappears in the time it takes to draw a breath.

It always feels the same. The sudden, overwhelming nausea; the narrow confines of the airlock holding her erect when she tries to fall; seawater churning on all sides. Her face goes under; vision blurs, then clears as her corneal caps adjust.

She collapses against the walls and wishes she could scream. The floor of the airlock drops away like a gallows. Lenie Clarke falls writhing into the abyss.

They come out of the freezing darkness, headlights blazing, into an oasis of sodium luminosity. Machines grow everywhere at the Throat, like metal weeds. Cables and conduits spiderweb across the seabed in a dozen directions. The main pumps stand over twenty meters high, a regiment of submarine monoliths fading from sight on either side. Overhead floodlights bathe the jumbled structures in perpetual twilight.

They stop for a moment, hands resting on the line that guided them here.

"I'll never get used to it," Ballard grates in a caricature of her usual voice.

Clarke glances at her wrist thermistor. "Thirty four Centigrade." The words buzz, metallic, from her larynx. It feels so wrong to talk without breathing.

Ballard lets go of the rope and launches herself into the light. After a moment, breathless, Clarke follows.

There's so much power here, so much wasted strength. Here the continents themselves do ponderous battle. Magma freezes; seawater boils; the very floor of the ocean is born by painful centimeters each year. Human machinery does not make energy, here at Dragon's Throat; it merely hangs on and steals some insignificant fraction of it back to the mainland.

Clarke flies through canyons of metal and rock, and knows what it is to be a parasite. She looks down. Shellfish the size of boulders, crimson worms three meters long crowd the seabed between the machines. Legions of bacteria, hungry for sulfur, lace the water with milky veils.

The water fills with a sudden terrible cry.

It doesn't sound like a scream. It sounds as though a great harp string is vibrating in slow motion. But Ballard is screaming, through some reluctant interface of flesh and metal:

"LENIE—"

Clarke turns in time to see her own arm disappear into a mouth that seems impossibly huge.

Teeth like scimitars clamp down on her shoulder. Clarke stares into a scaly black face half a meter across. Some tiny dispassionate part of her searches for eyes in that monstrous fusion of spines and teeth and gnarled flesh, and fails. How can it see me? she wonders.