The hatch was iron, set flush into the gun shop floor. Ada pulled it up. The smell came first — cold water, corroded metal, something organic that had been sitting in the dark long enough to stop being specific.
Leon shone the flashlight in. Iron rungs dropping fifteen feet into brown standing water.
Ada went down without looking at the rungs.
He watched her hands find each one. No hesitation. No pause at the bottom to orient — her feet found the ledge above the waterline and she was already scanning forward, weight easy, shoulders level.
He filed it and went down. Hope came after without being told.
The water ran knee-deep along the tunnel floor, pulling south. Pipes at shoulder height on both sides, concrete walls close enough to feel. The flashlight cone ahead left everything behind it worse. Dripping to the left. A mechanical thrum somewhere in the structure, deep and cycling, almost regular.
Ada moved without checking junctions.
At the first one — unmarked except for a drainage code — she turned left.
Leon caught up.
"You said the orphanage connects underground."
"I had a source."
"Ben."
"Yes."
"Ben didn't find that. You sent him."
A pause.
"You're using him to cover what you already knew."
Ada didn't slow.
"You knew this layout before we came down here."
She turned her head slightly. Not toward him.
"Keep moving."
Leon brought the flashlight up fast, sweeping the channel — nothing visible, nothing above the surface, just brown water and slow current. Then he understood.
Below the surface.
The wake was subtle — a line of displacement moving against the current, not with it. Something generating its own direction. His first read was crocodiles meant still water, bayous, drainage — not tunnel systems, not active flow, not this far inside the infrastructure.
The assumption lasted as long as it took the head to break the surface.
The jaw opened before the body was fully out of the water. The sound hit Leon's sternum before it reached his ears. Eight feet of animal coming out of a four-foot channel, the head already over the ledge, the mass still resolving in the dark behind it.
Leon fired. Head shot. The round deflected off the skull like it'd hit a curb. Fired again. Same.
"Go." He grabbed Hope's arm and pushed her forward. Not rough. Enough.
Ada was already moving, five meters ahead, not sprinting — controlled pace, preserving footing on the narrow ledge above the waterline. Right. Leon tracked it. That was right.
He fired two more rounds at the animal's neck where the plating was thinner and it reoriented toward him and that was wrong — he'd bought a second and spent it stopping instead of using it.
He ran.
The tunnel was too narrow for the animal to run parallel — it pushed its body into the channel and used the walls, half-swimming, half-walking its front legs along the ledge lip. Faster in the water than it should have been. Faster than he'd budgeted for. The tail swept in the channel and threw a wave that hit the ledge and his left foot went sideways in the spray and he caught himself on a pipe bracket and kept moving but the distance had closed.
Hope was ahead of him now. Ada beyond her.
His flashlight caught something on the left wall — a pipe, larger than the others, the housing around it sweated with condensation, a pressure gauge mounted above it. Older line. High-flow. The junction cap at the elbow was corroded at the seam, one of the bolts missing.
He got to it, drove his elbow into the junction, and the cap blew before he'd finished the swing.
Steam. Not a small amount. A concentrated burst that filled the tunnel in a half-second, scalding, directionless, pulling the flashlight into white and filling every angle at once. The crocodile hit it.
The head swung. The orientation broke. The thrashing sent water up the walls.
Leon was already moving blind through the steam, one hand trailing the wall, following the pipe line.
He heard Ada's voice. "Left. Step down."
He stepped down. His foot found a cross-brace above the waterline. The platform beyond it, a wider section, the steam thinning here.
He came through it.
His left side announced itself clearly — the pipe elbow had caught him across the ribs when he hit it, something that was going to compound everything that came after. He pressed on it once and stopped pressing.
The crocodile was behind them in the steam. Still moving, audible, working through the disruption.
He looked at Hope. At Ada.
"How far," he said.
Ada had her hand against the wall. Not steadying herself. Feeling for vibration.
"Close," she said.
The control section was older than the tunnels leading to it — gray concrete walls, a catwalk thirty feet up, work lighting mounted along the upper structure. Two of the lights on. Recent installation. Cables running down the wall that hadn't been there originally.
Leon saw it and stopped.
Ada kept walking.
"Wait."
She stopped.
He looked at the lights. At the cables. At the upper walkway where the shadows weren't moving but might have been settling differently than they should.
"Someone's been using this," he said.
"Yes."
He looked at her. "You know who."
Ada turned. "There's a control terminal at the far end. The access codes—"
"Ada."
She held.
"Who has access to this section."
A beat. "Annette Birkin," she said. "If she made it out of the station."
That landed. He looked at the walkway again.
The terminal was at the far end of the section, below the catwalk, visible from the entry. Between here and there: open floor, no cover, the two channels splitting around the central dividing wall, the catwalk above with clean sightlines to everything below.
"You knew she'd be here," Leon said.
"I thought she might use this access point, yes."
"You were planning to get to her."
"I need what she has."
"The G-virus samples."
Ada's expression didn't change. "The research. Annette has the last verified synthesis record. Without it—" She stopped. Turned. "The terminal. That's what matters right now."
"Stop," Leon said. "Back up. What do you need me for if you had all of this before—"
"Stop."
Female. Flat. Not loud.
Annette Birkin stood at the railing with a sidearm trained on Ada. Maintenance uniform, not hers — borrowed from someone in the facility who no longer needed it. Her other hand was on the railing, not for balance. To hold still.
Her gaze moved across the floor below. Leon. Ada. Hope. Back to Ada.
"Step away from the terminal."
Ada looked up. "Dr. Birkin."
Something tightened in Annette's face at the name. "You shouldn't be down here."
"The synthesis record doesn't survive this city without help," Ada said.
"It doesn't leave this city at all."
Leon stepped slightly forward. Not breaking the line. "We're not here for a fight."
Annette didn't look at him. "Then stop moving."
Ada shifted her weight. Small. Toward the terminal.
"Don't."
Ada moved anyway.
Half-step. Angle opening.
Annette fired.
Leon moved without deciding to. He hit Ada sideways and the shot caught his right shoulder and the floor came up and that was the sequence — no gaps in it, nothing to have done differently, just those three things in that order.
He got his left hand under him. Got one knee. His right arm was on the floor beside him, attached, not reporting. The shoulder hadn't resolved into pain yet — just pressure, a fullness that was going to become something else shortly.
Ada recovered behind him. He heard her weight redistribute. She was already moving.
Above, Annette moved away from the railing. Not toward them. Along the catwalk toward the far wall, toward a panel — he heard the key, the switch sequence, the sound of a large system being given an instruction it had been waiting a long time to execute.
Leon reached for the gun with his left hand. Tried to stand. Made it to one knee.
Hope was beside him.
He'd been tracking her position by habit — behind him, left — and she wasn't there, and then she was here, crouched to his level, two feet away, and what was happening to her arm was already past the early stage.
Not like the gun shop. Not contained.
The dark lines came up both forearms simultaneously and didn't pause at the elbow. They crossed it, branched toward the shoulder, thin and spreading, finding paths under the skin like pressure locating every available channel at once. The yellow came without sequence — her face, her neck, the backs of her hands, a warmth that read as fever from the outside and was something else entirely.
Her right arm was changing in a way that made sound.
Joints moving through angles they weren't made for, the kind of sound that registered in the teeth before the ears. Her fingers had passed full extension and kept going. The hand below wasn't a hand anymore in any useful sense — shape retained, function gone, the structure beneath rearranging without her direction.
She was watching it happen.
Her eyes went between her arm and Leon and her arm. She couldn't look away.
"Hope."
She looked at him.
"Still here," he said. "Stay here."
A sound came out of her — not words, not pain.
Her arm moved.
Not directed. The muscles firing in a sequence she hadn't chosen, the limb swinging wide, and the back of the changed hand hit the wall beside them. The sound it left in the concrete was wrong — deeper than impact, a depression that required more force than the material should have allowed.
She pulled the arm back against her chest. Held it there with the other one. Closed her eyes.
The system answered.
A pressure drop — ears, then chest, then the water at their knees changing direction before the sound fully arrived. Something below the floor reversed. The channels on both sides of the dividing wall went from slow to urgent in the space of two seconds, the current pulling south and building, and Leon understood what was coming.
He got upright.
Right shoulder rotating forward as he stood, disconnecting the arm below from reliable function. His left side from the pipe junction marked each movement with specific objection. He straightened to something close enough and looked for Ada.
She was at the dividing wall.
Already moving — she had Hope's left wrist, the arm that was still an arm, pulling her toward the narrow elevated platform above the split channels. The section of floor that would clear the surge. She hadn't waited to confirm Leon was standing.
Leon looked at the platform and took one step toward it. Stopped. The angle was wrong — Ada's line was faster but his right side couldn't manage the ledge grip, he needed a lower approach, he needed to know whether the current was already cutting across the dividing wall or just building—
The water arrived.
From the left channel first, then the tunnel mouth behind him simultaneously, a wall of it that filled the available space without ceremony. Just direction. South.
His feet left the floor.
His left hand caught a pipe bracket and his fingers closed on it and held while the surge tried to renegotiate. Two seconds. Maybe three.
The bracket was cold.
His shoulder made a final argument.
His fingers opened.
The south current took him.
He came up in the wider basin thirty meters on, the surge dispersing, his boots finding the floor without intention. Waist-deep. Moving but manageable. He stood.
The tunnel mouth behind him was still running high. The catwalk above it empty. The system still cycling somewhere in the walls.
No Ada.
No Hope.
He stood there.
The gun was still in his left hand. He didn't remember holding it through the water. It had just stayed.
He looked at the south passage.
Started moving.