The Swelling of the Shims

Iron nails bit into damp cedar overhead, each blow of the municipal hammers driving tremors through the subterranean beams. Jaromir knelt on a slimy pine catwalk, his oil lantern shaded beneath a wool apron. Above him, Magistrate Volkov's bailiffs were already nailing heavy oak planks across the bathhouse threshold. If Jaromir did not reach the master intake gate before the drainage siphon emptied the upper reservoirs, the sudden back-pressure would splinter the cedar channels and wash away whatever had jammed the sluice.

A floorboard creaked above his left ear.

"Bailiffs of Teplice!" Cedomir's great voice shook the subfloor timbers like a rolling thunderstorm. "Take heed of Municipal Ordinance Thirty-Four! Any nail driven into cured alpine larch without three drops of tallow violates the Thermal Preservation Act of 1342! You are bruising the city's dignity, lads!"

A muffled clatter followed, accompanied by angry swearing from the bailiffs. Jaromir exhaled through his nose and slipped off his leather over-boots. Barefoot grip was better on wet pine slime. He tied his chisel roll tight against his ribs, checked the ash mallet hooked to his belt, and eased his legs into the waist-deep black current of the lower intake flume.

The mountain run-off struck his ribs like a sheet of ice. Unlike the soothing forty-degree mineral pools upstairs, the subterranean intake carried raw meltwater channeled straight from the northern gorge. The current pulled hard against his shins, dragging him toward the narrowing siphon mouth thirty paces downstream.

Jaromir kept his shoulder pressed against the left flume wall. The rough timber had a language of its own. He felt along the planed joints with the flats of his fingers. Every two paces, an ash dowel held the heavy cedar staves in place. The wood was cold, taut, and properly swollen, the seams flush beneath their coat of rendered mutton tallow.

Nothing here had failed on its own.

He waded deeper, where the low tunnel dipped beneath the Lavender Grotto. The ceiling hung bare inches above his brow, forcing him to tilt his head back to keep his nose in the pocket of damp air trapped between the water and the joists.

At the junction box, the current twisted into a violent whirlpool.

The master sluice gate—a massive slab of seasoned heart-cedar four inches thick—was supposed to sit tight in its stone-lined groove, holding back twelve hundred gallons of freezing spring water until the evening replenishment cycle. Instead, the heavy gate hung cocked at an unnatural seven-degree tilt. A fierce jet of white water sprayed around the lower lip, roaring directly into the conduit that fed the cold plunge bath where Dragomir had been found.

Jaromir hooked his elbow over an overhead crossbeam to steady himself against the surging current. He unshaded the lantern with his free hand and held it low over the churn.

The gate had not jammed on silt or river gravel. A pale wedge of timber had been driven deep into the mortise slot on the eastern guide rail.

"Rotting timber, Volkov said," Jaromir muttered into the spray.

He reached beneath the churning water, his fingers finding the wedge. The grain felt dense, tight, and completely foreign. It was not buoyant mountain cedar or porous local pine. The wood was heavy and hard as iron beneath his fingertips, with the greasy, fine-pored smoothness of aged black walnut.

The saboteur had understood woodcraft all too well.

Cedar expanded swiftly in warm moisture, but shrank slightly when washed by icy meltwater. Walnut did the reverse. When carved bone-dry, a walnut wedge could slip into a lubricated guide track with barely a sixteenth of an inch of clearance. Once the freezing gorge water hit the grain, the cellular fibers drank the moisture, swelling outward with enough hydraulic force to lock a four-hundred-pound cedar gate solid against its track.

Jaromir took his narrow brass pry-bar from his roll. He wedged the bevel under the collar of the shim and leaned his body weight into the lever.

The metal bit into the cedar track, but the walnut wedge refused to budge. The wood had locked in its channel like a welded bolt. If he hammered carelessly, the brittle winter cedar of the main housing would crack, flooding the lower masonry vaults and giving the aldermen legal cause to demolish the entire south flume.

He ran his thumb along the grain of the wedge. The maker had angled the trailing bevel against the direction of the water flow, creating a self-locking ramp.

Jaromir swapped the pry-bar for a short-handled boxwood gouge and his ash mallet. Waiting for the next thunderous shout from Cedomir upstairs—"Three generations of bathers have soaked their chilblains in this grotto, and you hammer like apprentice coopers!"—Jaromir struck the chisel butt in precise sync with the noise above.

Two sharp taps into the cross-grain relieved the internal pressure along the wedge's center line. A fine ribbon of dark wood curled off beneath the steel.

The hydraulic seal cracked. A hiss of escaping air bubbled through the foam.

Jaromir hooked two fingers into the freshly carved groove and pulled with the steady, lifting heave of a timber-wright.

With a sucking pop that vibrated through the water, the wedge came free.

The master cedar gate instantly dropped down its guide track, slamming into its stone seat with a heavy, hollow boom. The roaring spray choked to a trickle. The surging current around Jaromir's waist quieted into a gentle, dark eddy.

Jaromir lifted the dripping wedge to the lantern light.

The shim was five inches long, carved with immaculate precision. Along the bevel, three shallow score marks—the distinct chatter of a master jointer's finishing plane—showed clearly across the dark walnut grain. Whoever had carved this had done so recently, in a dry shop, knowing exactly how many minutes of submersion it would take to jam the town's cold plunge.

Jaromir wrapped the wet walnut shim inside his dry apron and tucked it deep into his tunic.

He waded back toward the inspection hatch, the floor above vibrating with the heavy footsteps of the municipal watch.