The Under-City market hall of Sector 9 was an unmapped tangle of dripping pipes, corrugated sheet iron, and yellow gas flares.
Toby Mallow walked with his arms clamped across his chest, his oilskin coat bulging over the burlap sack of silver metal bars. Every time an overhead steam pipe hissed, Toby jumped slightly, his eyes darting between shadowed alcoves. Beside him, Barnaby trotted with heavy steps. The three-hundred-pound spotted burrow-hog was unperturbed by the grime, his flat snout snuffling along the cracks between floorboards for dropped cabbage stalks or spilled grain.
“Arthur, walk slower,” Toby hissed under his breath, adjusting his brass glasses. “Look at those three dockers by the valve station. They’ve been trailing our wake since we passed the fighting pit. If they realize we’re carrying two thousand silver credits, they’ll drop an iron grate on our heads and dump us into the sewage water gate!”
“They aren’t looking at the sack, Toby,” Arthur said without breaking stride. “They’re looking at Grimm.”
Grimm trotted half a pace behind Arthur’s left heel. The jet-black hound was silent, dark paws clicking lightly against damp oak planks. His coat, black as fiery dark rock, seemed to drink the flickering yellow light of sulfur lanterns. Whenever a dock worker or hooded smuggler glanced their way, Grimm’s single intact ear pivoted toward them. A low shaking hummed in his chest. A sub-heard warning that rattled loose rust from floor bolts.
The dockers at the valve station quickly turned their faces to the brick wall, pretending to inspect an empty steam pipe hub.
“Word spreads quickly in the drain pits,” Arthur murmured. He turned into a narrower tunnel labeled Shaft 14 — Geological Salvage. “They know what happened to the cyber-warg. Gutter scavengers don’t pick fights with beasts that crush silver-steel pistons on an empty stomach.”
“Still,” Toby muttered, clutching the sack tighter. “Two thousand credits! It’s the first time in seventeen years our combined net worth hasn’t been written in red ink with seizure notices attached.”
Arthur glanced back, the corner of his mouth curving faintly. “Hold on to that feeling, Toby. Because in forty paces, we’re spending three-quarters of it.”
Toby froze in the middle of the narrow high walkway. His jaw dropped, his round cheeks paling. “We’re... What? Three-quarters? Arthur! That’s fifteen hundred credits! Barnaby needs a clean bed of straw, and my boots have cardboard liners inside the soles!”
Barnaby let out a mournful squeal and bumped his snout against Toby’s hip.
“Good coats and clean straw won’t keep Vance court guards from kicking our clinic door off its hinges when the test trial opens,” Arthur said calmly, stopping before a heavy blast hatch at the end of the shaft. “Gregory Vance lost four guards in the alley last week. Julian’s faction won’t accept a commoner cadet retaining an independent Vanguard charter. If Grimm remains at Bronze E-Rank, he will fail the tactical pressure trials.”
Arthur raised his right hand and knocked four times on the rusted iron hatch: two slow, two rapid.
A heavy viewing slit slid back with a grating screech. Behind the slit, a pair of thick heavy-duty goggles gleamed in the dimness.
“Who knocks on Rust-Borer Dan’s inner wall?” a raspy voice demanded. “No scrap buyers after curfew.”
“The Butcher Medic,” Arthur replied evenly.
The silence lasted three heartbeats. Then came the sound of three brass deadbolts sliding back. It was followed by the clanking release of a drop-bar gearwork.
The heavy steel door swung inward.
The chamber beyond was a vaulted cave cut directly into earth-shaking bedrock beneath Mega-City 07. Rows of iron shelves stretched into the gloom, crowded with sealed lead canisters, carboys wrapped in wicker, and raw stone ore suspended in oil baths. The air smelled intensely of sulfur, dry ozone. The cold musk of ancient stone pulled from miles beneath the crust.
Behind a counter made from a salvaged excavator tread stood Rust-Borer Dan. The old prospector was barely five feet tall, his spine curved from forty years in drift mines. A clockwork breathing mask strapped across his sunken chest wheezed rhythmically.
Dan pushed his goggles up onto his greasy leather cap, squinting through bloodshot eyes at Arthur, then down at Grimm.
“Heard about you,” the old prospector grunted. “The kid who snapped an Iron-C warg’s jaw and stitched its pipes back together with pliers. Pit boss was furious he paid out twenty to one. Said you looked at a thousand-credit gladiator like a side of spoiled pork.”
“The warg had poor high-pressure upkeep,” Arthur said, resting his palms on the iron tread. “The seals were dry-rotted. I need deep-stratum stone reagents, Dan. Grade-1 deep-rock grade. Uncut, unbuffered.”
Dan coughed raspy in his throat. “The academy labs buy ninety percent of drift hauls before the mining cages reach the surface hoist. You got vanguard coin, boy? Or just that bloody apron?”
Arthur nodded to Toby.
Toby swallowed hard, a tiny whimper escaping his throat, before he hoisted the burlap sack onto the counter with a metal thud. He untied the hemp twine. He showed neat rows of box-shaped silver ten-credit metal bars stamped with the Vanguard Central Bank insignia.
Dan reached out, pulled a metal bar from the stack, and struck it against the iron counter. The metal rang with a clear, sustained pitch.
“Clean bullion,” Dan muttered. “Alright, cadet. What kind of poison is your hound chewing on?”
“Fifty drops of Abyssal Well Tar,” Arthur said. “Three hundred grams of crystal-hardened fiery brimstone from an active chimney pipe. And one liter of unpolluted underground spring salt water from the third underground water bed layer.”
Toby gasped, clutching his chest. “Arthur, well tar? That stuff is eighty credits a vial! It’s toxic waste from deep fissures!”
“It isn’t waste,” Arthur replied calmly. “It’s melted ancient dark rock rich in gravity heavy metals. Dan, do you have the third-stratum harvest?”
Dan stared at Arthur with wariness. “Most tamers who ask for well tar are black-market splicers trying to weld armor plates to drakes. It rots normal flesh in three days. Turns the stomach to black mush.”
“My hound doesn’t have normal bone marrow,” Arthur said.
Dan grunted, turned, and shuffled into the back racks of the vault. He returned five minutes later carrying a lead-lined case and two sealed glass demijohns.
He set the lead case on the counter and clicked the brass toggles open. Resting in a bed of dry ash was a thick glass vial wrapped in copper wire. Inside sloshed fifty drops of pitch-black fluid so dense that it barely moved. Even sealed beneath the lead lid, the surrounding air above the vial seemed to dip half an inch. It bent the lantern light with a subtle gravity sink.
Beside the case, Dan set down a cloth sack containing yellow, semi-clear crystals that reeked of brimstone. A heavy clay flagon filled with stone-heavy water.
“Fifty drops of virgin well tar, tapped from the three-thousand-meter rift fissure below Sector 9,” Dan recited. “Three hundred grams of chimney pipe brimstone crystals, ninety-eight percent pure. One liter of third-underground water bed salt water, zero surface contaminants. Total price: fourteen hundred and fifty credits. Take it or leave it.”
“Fourteen hundred and fifty!” Toby wailed, clutching his collar. “Master Dan, look at our coats! Have mercy on two honest academy cadets!”
“The price is fair for unbuffered yield,” Arthur intervened. He counted out one hundred and forty-five silver metal bars from the sack, stacking them into gleaming columns. “Wrap the vial in heat padding wool. If the tar drops below twelve degrees before we reach the clinic, the gravity mid-air will precipitate.”
Dan raised an eyebrow, impressed. “You know your handling protocols, kid.”
The old prospector packed the reagents into a padded canvas crate. Then he pushed it across the counter.
Arthur lifted the crate. The weight was substantial—nearly thirty pounds for a modest parcel. It was driven by the huge thickness of the well tar. As Arthur settled the strap across his shoulder, he adjusted his monocle magnifying glass.
Amber glyphs lit up across the aiming cross of his left eye, analyzing chemical purity through the glass:
The formulation was clean.
“We have our spark,” Arthur said, turning toward the exit. “Toby, secure the leftover five hundred and fifty credits. We need beef bones, cabbages for Barnaby, and three blocks of ice from cold storage.”
“Ice?” Toby blinked, scurrying after Arthur as Dan dropped the deadbolts behind them. “Why do we need ice? It’s forty degrees in the clinic already!”
“Because during the breakthrough, Grimm’s body-energy core will reach forty-two degrees,” Arthur explained, his stride steady and rapid. “If we don’t submerge him in an ice-saline bath during the marrow infusion, the brimstone reaction will boil his brain spinal fluid.”
Toby shuddered, casting a nervous glance down at Grimm.
The black hound was trotting close beside Arthur’s knees. He lifted his black muzzle, sniffing near the canvas crate. The pungent aroma of brimstone drifted through the seams. Then, Grimm wrinkled his nose and gave a sharp sneeze. It shook his massive head.
Then, recognizing the stone deep ring humming within the well tar, Grimm’s amber eyes widened. A low whine of excitement escaped his throat. He pressed his broad head against Arthur’s thigh. He walked so close that his black glass flank brushed Arthur’s coat with every stride.
“He knows what it’s,” Toby muttered in awe. “Don’t you, boy? You know that black mud is going to make you a total terror.”
Grimm gave a slow wag of his tail, the muscle of his hindquarters rippling beneath his scarred hide.
They climbed the stone stairs out of Sector 9, emerging through the street grate into the gray drizzle of Slum Ward 9. Twenty minutes later, they pushed open the weathered oak door of the clinic.
The clinic was quiet. Zinc tables stood scrubbed and clean, jars of dried herbs and stitch needles neatly arranged on timber shelves. Arthur set the test chemical crate on the main slab, unbuckled his work bracers. Then he walked to the cast-iron stove.
Grimm trotted across the scrubbed floorboards, walked straight to Arthur’s leather field boots drying near the hearth. Then it flopped down with a heavy thud. He rested his broad chin directly across the toe caps, amber eyes half-lidded. He watched Arthur light the burner.
“Rest while you can, Grimm,” Arthur said softly. He set the iron kettle on the flame to heat sterile saline. “In three hours, we restructure your long bones.”
Grimm let out a deep groan, closed his eyes, and began to snore.