The cold rain of late spring had turned the southern pass into a trough of yellow, liquefied clay that sucked at the leather boots of the laborers until every step was an act of brutal endurance. The pass was a narrow notch between two limestone bluffs, the only gap where a wagon or a troop of horsemen could enter the valley without scaling the sheer crags of the upper ridge. Here, where the hills formed a natural bottleneck, Thomas had drawn his line.
He stood on the muddy slope of the western bluff, his woolen cloak soaked through and clinging heavily to his back. The wind blew from the south, carrying the smell of wet pine and the distant, stagnant rot of Baron De Born's unmanaged lowlands. Below him, eighty men from the factory and the brick-kilns were bent double over long iron-tipped shovels, their breathing a ragged, collective wheeze against the steady roar of the rain.
They were digging a standard Roman-style defensive ditch—a fossa—twelve feet wide at the lip, six feet deep, and tapering downward to a V-shape that would snap the legs of a charging horse or capsize a supply cart. The clay they excavated was not thrown away; it was piled on the northern bank of the trench, forming a high earthen rampart that Wat's boys were already reinforcing with interlocking wattles of split willow and hazel.
"The grade is too steep on the western section, my lord," Elias said, climbing up the slippery bank with his sheepskin map rolled tight inside a greased leather tube. His boots were encased in thick clods of clay, making him look clumsy despite his usual light frame. "The rainwater is pooling in the middle instead of draining toward the flume. If the bank turns to soup, De Born's horsemen won't need to clear the ditch—the ditch will simply slide down the hill."
Thomas pulled his eyes from the line of shovels. He reached into his pocket and checked the device, shielded from the downpour by the thick folds of his tunic.
Battery: 68%
He didn't open the databases. He didn't need to look at a diagram of a Roman camp to understand fluid dynamics. He looked at the water overflowing from the diversion canal—the secondary channel he had engineered to carry the waste-water away from the Great Hall of Wheels.
"We don't drain it, Elias," Thomas said, his voice flat. "We fill it."
Elias blinked, wiping a mixture of rain and soot from his forehead. "Fill it? A wet ditch is an unstable thing, Thomas. If the water undermines the limestone shelf beneath the dirt, the entire pass could collapse."
"We use the overflow from the water wheel flume," Thomas explained, pointing back toward the smoky silhouette of the factory down the valley. "We build a timber sluice gate at the top of the western slope. If the scouts come, we open the gate. The water doesn't just fill the trench; it turns the entire bottom of the pass into a waist-deep mire of moving silt. A knight in sixty pounds of mail won't be able to lift his feet, let alone swing a sword."
Elias looked down at the V-shaped trench, his analytical mind tracking the path of the water. A slow, appreciative nod turned into a grim smile. "A hydraulic barrier. You aren't just building a wall, Thomas. You are turning the river into a constable."
Down in the muck of the ditch, Master Cerdic was shouting at a pair of young weavers who had stopped to wring the freezing water from their linen smocks. The master weaver's indigo-stained face was raw from the wind, but he held his heavy ash pole with the grim authority of a man who had found a new use for his gnarled hands.
"Keep the iron moving!" Cerdic roared, his voice cracking over the sound of the rain. "Every inch of clay we lift today is an inch of dry floor for your babes tomorrow! You think De Born will give you scrip for your wool? He'll take the wool and leave you the whip!"
The men grunted, their iron-tipped shovels biting back into the yellow earth. They were tired, their muscles unaccustomed to the lifting of wet stone and clay, but there was an order to their movement that had been learned on the factory floor. They didn't move like a chaotic mob of feudal peasants; they worked in shifts, four men digging while four men cleared the barrows, their timing regulated by the distant, rhythmic whistle of the steam engine that echoed from the silver mine every twenty minutes.
Victoria appeared from the willow grove at the base of the bluff, leading a small cart drawn by one of the manor's sturdy draft horses. The cart was loaded with large iron cauldrons that gave off a thick, savory steam—a rich broth of beef tallow, barley, and the salted cod Thomas had imported from the coastal traders before the quarantine.
"The work stops for twenty minutes," Victoria called out, her voice clear and carrying over the ditch. "Come get your lard and grain!"
The men dropped their tools with a collective groan, scrambling up the muddy bank toward the cart. They were given thick wooden bowls of the boiling soup, their hands shaking so violently from the cold that half the broth spilled into the muck before it reached their lips.
Thomas walked down to the cart, taking a bowl from Victoria. Her hands were red from the steam, her leather apron spattered with grease and yellow clay.
"The merchant from Oakhaven arrived at the northern markers," she said softly, watching the men eat. "He has three wagons of iron ore from the southern hills, but he refuses to take the manor scrip. He says the King's officers in the city are arresting anyone found with paper that doesn't bear the royal mint."
Thomas took a sip of the salty broth, the heat of it a sudden, burning comfort in his chest. "Did he take the cloth?"
"He took five bales," Victoria said, her jaw tightening. "But he demanded two pieces of silver coin for the difference. Our vaults are growing light, Thomas. If we cannot use the paper outside the valley, the silver hill will belong to the merchants before De Born ever reaches the gate."
Thomas looked down at his phone through the gap in his cloak. He had no new messages—the rain and the distance from the origin point seemed to damp the signal—but he opened his personal ledger app, tracking the balance of his primitive central bank. He was running a classic liquidity deficit; his internal production was booming, but his currency was an island in a sea of medieval bullionism.
"We don't pay him in silver next time," Thomas said. "We tell him that if he wants our fine-weave cloth, he must pay twenty percent of the price in his own iron ore, and we will credit the rest against his future taxes in Oakhaven. Elias says the Archbishop is going to grant us a market charter next month. Once that seal is on the parchment, the King's officers won't dare touch the paper."
"And if the charter is delayed?" Victoria asked.
"Then we make the cloth so cheap that the merchants will risk the gallows to get it," Thomas said.
He turned back toward the ditch, where Wat was now arriving from the forge. The blacksmith was followed by three boys carrying long bundles wrapped in greased burlap. Wat walked with a heavy, limping stride, his leather apron stiff with iron filings and oil.
He stopped in front of Thomas and threw down one of the bundles. The burlap fell away, revealing six heavy pike heads of a dark, dull blue steel. They were different from the standard medieval weapons; instead of a simple leaf-shaped blade, Thomas had designed them with a long, square-section spike—an armor-piercing bodkin point—and a cross-bar three inches below the tip to prevent a wounded knight from sliding down the shaft to reach the defender.
Wat picked up one of the heads, his rough thumb checking the alignment of the iron ears that would be riveted to the ash pole. "The carbon is right, Thomas," the smith said, his single eye glittering under his wet cap. "We used the slag from the engine furnace to reheat the bloom. It's hard enough to bite through a horse-archers shield, and it won't snap if a lance hits it oblique."
"How many have you cast?" Thomas asked, touching the cold, blue metal.
"Forty," Wat said. "Cerdic's boys have been cutting the ash poles in the north woods. We'll start the riveting tonight in the barn."
Thomas looked down into the trench, where the men were already throwing their empty bowls back into the cart and reaching for their shovels. The rain was beginning to slacken, the heavy grey clouds breaking to reveal a thin, watery line of yellow light along the southern horizon.
Suddenly, a sharp, high-pitched whistle cut through the valley from the southern ridge—the sound of an iron whistle Thomas had given to the scouts three days ago.
The men in the ditch froze, their shovels poised over the clay. Master Cerdic reached for his ash staff, his knuckles turning white through the indigo stains.
"They're here," Elias whispered, looking toward the notch in the hills.
Thomas reached into his tunic and unlocked the phone screen. No texts had arrived, but the compass app was steady, the arrow pointing due south toward the gap where the yellow light was breaking. He didn't feel the panic he had felt during the first week in the mud; he felt the cold, clinical focus of an engineer whose system was about to be tested under a live load.
"Wat, get the pikes," Thomas commanded, his voice carrying down the line of the rampart. "Cerdic, get your ranks into the V. We're about to find out if the ditch holds the weight."