Reading the Silt Trace

The reversed intake current did not give Boróka time to fight the drop. Thirty thousand horsepower dragged her down the intake throat like lead ballast, dragging silt and sheared fiberglass across the faceplate of her dive mask. Below, forty fathoms deep in the bedrock casing of Lock Seventeen, the secondary turbine hub screamed as its bronze impellers chewed through the backwash.

She dug both gloved thumbs into the masonry joints of the conduit wall. The suction ripped at her shoulders, but her right magnetic boot found the lip of an emergency bypass chute. Three feet above the churning blades sat a cast-iron service scuttle, rusted shut under forty seasons of river muck. Its manual release dog was locked tight with an anchor pin.

Boróka wedged her knee against the chute frame, reached up, and slapped her bare palm over the pin's corroded cotter. Her throat burned with the dry, chemical scorch of her earlier breach, but the turbine blades were already throwing up white cavitation foam against her boots.

She did not draw breath through her mouthpiece. She clamped her jaw, centered the tone behind her nasal bridge, and drove a single, razor-sharp 620-hertz pulse straight into the iron.

The brittle alloy shattered inside the sleeve. Metal fragments peppered her palm. She hammered the release dog with her pry-chisel, shoved the hatch upward against the current, and scrambled into the dry air pocket of the maintenance shaft.

The hatch slammed shut behind her under tons of hydraulic backpressure. Boróka collapsed onto the rusted grated deck of the gallery, tearing her dive mask off with shaking fingers. She coughed violently, bringing up salt and the copper tang of blood from her scorched vocal cords. Her laryngeal nerves throbbed beneath the collar, every pulse sending needles of heat into the base of her skull.

She unclipped her harness, checked the padded canvas holster at her chest, and found the ten-inch beryllium bronze cylinder secure.

"Still in one piece," she croaked. Her voice sounded like crushed gravel.

The maintenance conduit ran half a mile along the lock's south abutment, dripping brown brine from expansion joints into dark drainage troughs. She climbed a slick maintenance ladder, pushed through an unmonitored storm-flap, and stepped onto the damp wooden planking of Grotto Nine.

The grotto was an undercut cavern hollowed beneath the lock’s basalt foundations, filled with diesel exhaust, damp river mist, and the quiet slap of tidal chop. Tied to a rotting mooring bollard sat the Csóka.

The thirty-foot hydrofoil skimmer looked like a jagged waterbug built from scrap titanium and salvaged turbine cowlings. Its twin surface-piercing hydrofoils were retracted, tucked against the hull like insect legs, and its muffled turbine hummed on low idle.

A broad-shouldered figure in a stained oilskin coat leaned over the skimmer's open cockpit, grease gun in hand.

"You're twelve minutes late," Erzsébet Radványi called without looking up. She wiped a smudge of graphite grease from her cheek with the back of a calloused hand. "I was about to untie the lines and tell your cousins the lock had swallowed you whole."

"Turbines... reversed early," Boróka rasped, swinging her legs over the Csóka's gunwale and dropping onto the grated deck.

Erzsébet turned, her sharp gray eyes narrowing at Boróka’s neck collar. Without a word, the older woman reached into her tool harness, pulled a thick syringe tube of concentrated potassium-saline gel, and shoved the rubber tip between Boróka’s cracked lips.

"Swallow it before your vocal chords seize into raw leather," Erzsébet muttered. "Between the salt marsh and your suicide runs, that throat will pickle your liver years before the Seawall Authority manages to string a noose around it."

Boróka grimaced as the thick, salty slurry coated her raw pharynx. The burning subsided into a dull, numb ache, the electrolytes soaking into her depleted tissues like rain hitting sun-cracked mud. She blew out a slow, steady breath.

"The courier skiff didn't run aground by accident, Auntie Erzsi," Boróka said, her voice smoothing out into its usual low rasp. She reached into her dive suit and produced the beryllium cylinder. "Its hull was breached before the intake ever pulled it under. The crew never even managed to dump their avionics."

Erzsébet stared at the bronze casing, the grease gun freezing mid-motion in her grip. "A Danubian naval vault cylinder. Where did you pull this from?"

"The avionics vault behind the pilot's station. It took four hundred hertz just to pop the hatch clamps to get inside."

Erzsébet took the cylinder, testing its balance with an engineer's practiced touch. "Beryllium bronze with vacuum-sealed cryogenic baffles. This isn't river league mail, Boróka. This is high-command operational gear."

"Can you read the disk?"

"If I can't, no one between here and the delta can." Erzsébet climbed down into the narrow cockpit pit and plugged the cylinder's brass terminal interface into the Csóka’s modified navigation console.

The skimmer’s cockpit smelled of burnt copper, salt grease, and old coffee. Erzsébet bypassed the encryption pins with a pair of fine copper jumpers, muttering under her breath as cathode dials flickered green along the wooden dashboard.

A high-frequency spool whined inside the cylinder. Data lines scrolled across the green phosphorescent display, scattering coordinates and acoustic frequencies across the glass.

Boróka leaned over Erzsébet’s shoulder, her fingers tightening on the back of the pilot seat. "What is that? Those aren't cargo manifests."

"No," Erzsébet whispered. Her blunt fingers drifted over the keyboard, tapping out filter queries. "They're bathymetric telemetry streams. Slaved to a deep-keel inertial guidance loop."

The screen flickered. A schematic wireframe resolved on the phosphor monitor: a sleek, predatory hull over two hundred feet long, ribbed with acoustic absorption tiles and carrying twin seismic-cavitation torpedo tubes in its ventral bay. Above the hull, a stark military designation blinked in amber light:

AUTONOMOUS SUBMERSIBLE UNIT: KÁRPÁT-NULL

MISSION STATUS: UNTETHERED / CYCLIC RUN

"That's the ghost," Boróka breathed.

"It's worse than a ghost," Erzsébet said, her voice dropping into cold gravity. She pointed a grease-stained thumb at the vector line descending across the trench contour map. "Look at the terminal target coordinates. Azimuth zero-nine-four, depth forty fathoms, velocity forty-two knots."

Boróka traced the glowing vector. The green line terminated directly beneath the bedrock footing of Lock Seventeen's primary basalt pylon.

"It isn't patrolling," Boróka said. "It's locked into an automated terminal strike. If those tectonic torpedoes detonate under the sill, the entire middle basin collapses. Two million tons of ocean will wash every islet from here to the southern shoals off the map."

"The courier wasn't running contraband," Erzsébet said, pulling the diagnostic jumper and killing the screen glare. "They were trying to deliver the shutdown frequencies before the drone entered firing range. And whoever scuttled them wanted Lock Seventeen drowned."

A heavy mechanical clank echoed from the mouth of the grotto.

Through the drifting curtain of river mist, the yellow arc of a sixty-thousand-candlepower naval searchlight swept across the water, illuminating the dripping basalt stalactites and turning the spray into blinding silver.

Then came the blast.

Two long, sonorous horn blasts rolled over the chop, precise and deafening. It was the legally mandated restricted-waters signal of the Continental Seawall Authority, sounding with bureaucratic perfection across the darkness.

"Patrol cutter," Erzsébet hissed, her hands flying to the ignition toggles. "One of their tactical hounds caught our wake."

Boróka drew her hood up, clipped the telemetry cylinder to her chest ring, and dropped her hand onto the Csóka’s throttle lever. "Drop the foil latches, Erzsi. He's sounding the approach rulebook, which means he's about to ram."