The yellow-green fog parted under the impact of four thousand charging bodies.
Surging through the withered marsh scrub came the vanguard of the Black Fen. A writhing, clicking wave of six-legged mire-hounds, their barbed tails whipping in frenzy, their bone jaws snapping with the sound of a thousand shears.
Behind them surged two thousand bloated leech-crawlers, their segmented back shells glistening with acidic slime as they dragged their heavy bodies across the peat mud.
They didn’t slow. They didn’t hesitate.
Driven by the telepathic spore-pulse of Hesketh the Rot-Weaver, the swarm threw itself into the dry outer ditch at forty miles per hour.
The ditch had been engineered with a steep forty-five-degree counterscarp, twelve feet deep and twenty feet wide, lined along its entire floor with the dense, linked abatis.
Thousands of sharpened spruce crowns, their branches trimmed to needle-sharp points and bound with green withy, faced outward into the teeth of the charge.
CRACK-THWUMP. CRACK-THWUMP.
The lead wave of mire-hounds slammed into the abatis head-first.
Sharpened spruce stakes, fire-hardened and angled toward the marsh, pierced through soft underbellies and locked between armored thorax plates.
The sheer driving force of the charge worked against them. The front ranks were impaled on the timber stakes. Then, the following ranks piled in behind them, driven forward by the weight of thousands of thrashing bodies.
Within thirty seconds, the dry ditch became a churn of thrashing legs, snapping jaws, and screeching monsters.
Captain Kenneth Drake stood upon the low roof wall of Sluice Tower One. His tin snout strapped was tight, his sword raised high above his head.
“Arbalestiers on the firing steps.” Kenneth roared, his voice cutting through the thundering screech of the pit. “Squads One and Two, loose on the ditch lip! Keep the crawlers off the timber crest.”
Along the low roof wall, eighty Grey Crag militia men raised their heavy steel crossbows.
TWANG-TWANG.
A disciplined volley of iron-tipped bolts hissed into the ditch at two hundred paces.
The bolts, tipped with hardened pig-iron broadheads poured from the new blast fire, punched through the softer eye-sockets and neck-joints of the trapped beasts with devastating smooth speed.
Mire-hounds shrieked, their limbs thrashing as black, acidic ichor pooled in the bottom of the trench.
“Squads Three and Four, advance and loose.” Kenneth commanded. “Maintain the cycle! Don’t let them climb over their own dead.”
A second volley struck the writhing mass.
Another two hundred beasts collapsed into the tangle. But the sheer, horrifying volume of the swarm was relentless.
Four thousand more hounds and leeches poured out of the yellow fog, scrambling directly over the writhing bodies of their impaled comrades.
The corpses in the ditch were beginning to form a ramp of dead flesh.
Within two minutes, the depth of the ditch had been halved. The leading edge of the swarm was clawing at the outer timber stone retaining walls of the main levee.
The shape of the abatis had been refined from the early winter defense works at Rustgate.
Kenneth Drake leaned over the stone coping, watching the beasts tangle themselves in the laced spruce branches.
“We learned this on the north wall during the wolf winter,” Kenneth said. His voice carrying the was calm satisfaction of an old soldier watching a proven drill. “Pines felled with butts facing inward, crowns pointing outward, laced together with green withy at thirty-degree angles.
When a beast charges, its own forward heavy rush drives the spiked branches deeper into its hide. The more it struggles, the tighter the wood binds around its joints.”
Duchess Rowena watched the thrashing mass with a commander’s sharp eye.
“A horse-tangle,” Rowena noted, her knuckles resting on the handle of her sword.
“The Dun-Krag tunnel diggers used it against the border clans. But they never used pine boughs to trap four thousand swamp monsters at once.”
“Wood is cheap, and green withy is plentiful along the drainage cuts,” Giles replied, adjusting his glasses.
“A passive entanglement belt needs zero upkeep, consumes zero ammunition, and converts the striking force of an incoming assault wave directly into decelerating load-bearing friction.”
Duchess Rowena stood beside Kenneth. Her gauntleted hand gripped her broadsword, her cold blue eyes widening with grim urgency.
“The ditch is filling, Captain.” Rowena shouted over the screeching din. “In three minutes, they will walk across their own dead and reach your stone wall!
Call down my heavy lancers! We must charge the ditch shoulder before the line is overrun.”
Giles Croft stepped forward. His wooden ruler was tucked under his arm, his stopwatch held firmly in his palm.
“Cavalry deployment into a ditch filled with impaled monsters and acidic ichor would result in ninety percent mount casualties within thirty seconds,” Giles said calmly. “It’s an atrocious waste of horseflesh.”
Rowena spun on him, her sword blade gleaming in the torchlight. “Then what’s your answer, clerk? The monsters are climbing.”
“They’re occupying the pre-set chemical reaction troughs,” Giles replied.
He walked to the corner of the low roof wall. There, a heavy iron trip-lever was connected to four copper tension cables running down into the ditch foundation.
Directly beneath the floor of the abatis trench lay twelve wooden water chutes, packed with fifty tons of dry, unslaked burning lime powder pebbles and covered by punched holes in timber grates.
“Unslaked calcium oxide,” Giles explained, checking the sweep of the second hand on his watch. “Fifty tons of chemical potential energy waiting for water.
The water table in the canal race is currently at plus eight feet. Toby... Release the slaking water gates.”
Toby Karr threw his weight onto the backup high-pressure trip-lever.
CLANK-BOOM.
Four underground water gate gates dropped open.
Five hundred gallons of cold canal water surged through underground timber channels. It poured directly into the dry burning lime powder troughs beneath the feet of the thrashing monsters.
For two heartbeats, there was only a low, underground gurgle.
Then, the chemistry of the earth blew up.
KA-ROOOOOOOOOM.
A violent, total geyser of boiling white steam erupted from the bottom of the ditch with the force of an unsealed fiery vent.
The heat inside the confined trench spiked from fifty degrees Fahrenheit to over three hundred degrees in less than three seconds.
The unslaked burning lime powder, instantly reacting with the plunging torrent of canal water, generated an overwhelming exothermic reaction that boiled the water into high-pressure steam.
The boiling slurry surged upward through the punched holes in floor. It wrapped two thousand five hundred trapped mire-hounds and leech-crawlers in a blinding, scalding fog of skin-burning calcium hydroxide.
The shrieks that rose from the ditch were unlike anything the defenders had ever heard.
The boiling bitter-salt chemical didn’t merely burn.
It dissolved organic proteins. It melted the soft connective tissue between the beasts’ hard shell plates.
The boiling lime slurry seeped into their breathing spiracles, blinding their eyes and scorching their internal organs into grey mush within seconds.
The heat was so intense that the monsters’ own moisture boiled inside their back shells, causing the black hard shell shells to rupture outward with thousands of wet, explosive pops like roasting chestnuts.
A dense cloud of boiling white steam rolled forty feet into the night sky. It smelled of scorched marrow and wet lime plaster.
Across the entire two-hundred-yard ditch section, the thrashing stopped.
The living ramp of monsters collapsed into a smoking, motionless slurry of stone-hard grey bone, melted hard shell, and boiling white mortar that settled into the bottom of the trench like cooling porridge.
On the low roof wall of Sluice Tower One, Duchess Rowena slowly lowered her broadsword.
Her hands were shaking inside her steel gauntlets.
Her face, lit up by the dying glow of the steam cloud, was pale with total, stunned horror.
“Gods of Highmarch,” Rowena whispered, her voice cracking as she stared into the smoking ditch. “You... You boiled them alive in their own shells.”
“It’s standard exothermic slaking,” Giles said, wiping water drops from his glasses with his handkerchief. “Fifty tons of calcium oxide releases about sixty-four gigajoules of heat energy upon complete hydration.
The resulting calcium hydroxide neutralizes the acidic ichor and petrifies the corpses into a stable high-pressure ground base. We have permanently solved the settlement issue along the outer counterscarp.”
Rowena stared at him, her mouth opening and closing without sound.
Beside her, Kenneth Drake let out a low, grim chuckle behind his tin snout.
“I told you, Your Grace,” Kenneth murmured. “The Lord Baron doesn’t fight monsters. He mixes concrete.”
Before Rowena could find her voice, the water in the main canal channel began to churn with sudden, violent rough churning.
A ground-shaking wave surged through the ditch, splashing three feet of foam over the concrete doorstep.
Out in the deep marsh, fifty yards beyond the smoking trench, the dark water parted like a curtain.
Rising into the moonlight, towering sixty feet above the reeds, rose the huge, three-headed dark shape of the Three-Headed Rot-Hydra.
Its three crested heads reared into the yellow fog, their jaws swelling with blazing bright, skin-burning green bile that lit up the night in a sickly, emerald glare.
Sister Teresa of the Pure Cistern stood upon the backup watching platform. Her linen wimple pinned was tight against the wind. She held a copper anemometer to measure the rising breeze.
Beside her, two hospital new students held high-pressure brass spray lances, coating the stone low roof wall in a fine, misting barrier of wet lime plaster and harsh cleaning acid.
“The air is cleansed,” Teresa reported, her voice steady and clear through her tin snout.
“The wind blows toward the south at four miles per hour. The steam will carry the skin-burning vapor back into the eyes of the horde.”
Rowena looked from the steaming ditch to the glowing emerald sphere hovering over the deep marsh half a mile away.
“The shield of the Broodmother,” Rowena said, her voice dropping into a solemn, ancient dread. “The chronicles of Highmarch record that in the Second Cataclysm, an entire ducal army under Duke Aldous the Third surrounded this beast with forty heavy trebuchets.
They rained six-hundred-pound granite boulders upon her barrier for three days, and the emerald sphere didn’t yield a single crack. It’s a total cosmological ward, Lord Croft. Physical force can’t breach it.”
“Every physical structure has a working boundary condition,” Giles replied calmly. “The mages of your Second Cataclysm failed because their trebuchet stones struck at eighty feet per second.
When striking force is delivered slower than the shield’s internal refreshment cycle, the lattice redistributes the load. But when speed exceeds the speed of sound... The lattice has no time to respond.”
Surrounding the titan hovered the iron-hard, thirty-yard dome of its emerald mana-shield. It hummed with ancient, ancient power.
The Broodmother had arrived.