The Sentry at the Willow Bridge

How many minutes does it take to secure three quartz prisms, one mule, and eighty pounds of clockwork mirrors before an artillery column levels the stable?

In the lantern light behind the Red Willow Tavern, I decided the answer was six. If I took seven, Duke Oluwaseyi’s brass guns would find me fumbling with buckles, turning my wagon into kindling and my mechanical dog into scrap.

I slid the ruby quantum crystal into its felt-lined compartment beneath the wagon bench. The stone clicked home. Beside it went the sapphire prism, then the fluted copper condensing lenses that gave my tabletop dragons their shimmering scales. The Gilded Moth was not built for war. She was a creaking box of painted ash-wood, roofed in tarred canvas, with two polished exhaust flues poking through her ceiling like brass ears. When she rolled down cobbled paths, her hanging tin pots chimed like bells. Silence was not in her nature.

"You pack like a thief running from the bailiff," a low voice muttered from the stall door.

Mma-Adu stood in the opening, a heavy basket against her hip. The tavern keeper wore a thick indigo shawl against the river damp, her dark eyes sharp under the rafters. She did not look like a woman who had spent the last few minutes reading stolen military timetables.

"Thieves steal gold, Mma," I said, yanking a cinch strap tight around a crate of wick-oil. "I am merely borrowing the road before someone points a twelve-pounder tube at my wheels."

"Take these." She thrust the basket into the wagon bed. A linen towel covered warm salted yam cakes and three smoked catfish wrapped in banana leaves. "The map says their grid is set for the third watch. If you stay on the north canal, their scouts will box you in before you reach the bend."

"Then I take the southern towpath."

"The southern towpath has a bridge at the willow narrows," she countered, helping me thread the trace-chains to the wagon pole. "An old stone arch with timber decking. If Oluwaseyi's forward picket is watching the road, that bridge is where they will stand."

"Then I shall smile, tip my velvet hat, and pretend to be an idiot selling cabbages."

"You already have the hat," she said dryly. "The cabbage part will require no effort at all."

A rhythmic tapping sounded beneath my boots. Pipu trotted out from behind the hayrick, his brass snout coated in chaff. The little clockwork terrier shook himself with a violent rattle of copper plates, his internal escapement ticking like an agitated watch. He stopped at my ankle, raised his right foreleg, and let out a dry, metallic squeak. His mainspring was running thin.

I knelt, pulling the four-pronged brass key from my waistcoat. "Come here, copper-ears."

I slid the key into the socket behind his shoulder blades and turned it three firm rotations. The interior ratchet growled. On the fourth turn, the spring caught with a stubborn whine, buzzing like a hornet trapped in a tin cup. Pipu gave an indignant jerk of his head, lunged forward, and clamped his miniature jaws around the trailing hem of my apron, tugging with all the furious determination of a ten-pound bundle of gears.

"Let go, you menace," I whispered, prying his cold brass teeth free. "We have miles to cover before the third watch ends."

I hitched Kishi, my sway-backed gray mule, between the shafts. The beast gave a mournful snort, smelling the damp canal fog through the yard gate, but leaned into the harness with sullen obedience.

Mma-Adu pressed a small pouch into my palm. It smelled of dried mint. "A blend of bitter wormwood and river sage. Burn a pinch on your brazier if the midges get thick."

"Thank you, Mma. When the cannons are gone, I will come back and project a three-headed river serpent across your taproom ceiling. Free of charge."

"May the ancestors preserve me from such generosity," she said, but her palm rested against my sleeve for a brief beat before she pushed me toward the gate. "Go, lantern-master. The green is crawling with officers."

I led Kishi into the dark lane.

Omu-Adu was quiet, but the quiet had a sour smell: wet charcoal, river silt, and the ozone tang of matches. Farther north, across the green, yellow dots of light moved among the trees where Oluwaseyi's engineers drove iron stakes to measure firing lanes. We turned south, slipping down the narrow alley between the weavers' sheds, where willow branches swept low over the brick walls.

The Gilded Moth rumbled softly over the damp earth. Pipu sat on the buckboard beside my knee, his glass-bead eyes catching the faint sheen of misty moonlight.

At the end of the lane, the canal opened wide. Mist hung over the water in milky sheets, swirling around the red-brick pillars of the Willow Bridge. The stone arch spanned the lock spillway, forty paces across. Beyond it lay the open southern towpath, leading toward the river marshes where no siege guns could follow.

Halfway across the bridge stood an iron tripod lantern. Beside it leaned a sentry.

He wore the river-gray wool coat of Duke Oluwaseyi’s vanguard infantry. A brass-banded matchlock musket rested across his shoulder, its slow match glowing like a red coal in the mist. Across the bridge approach, he had stretched a spiked hemp barrier, blocking the road.

Kishi stopped, his long ears swiveling forward with a soft huff.

There was no turning back. The alley was too narrow to turn an eighteen-foot wagon, and backing a mule across two hundred yards of mud would bring the vanguard down upon our heads.

I reached beneath the buckboard and lifted Pipu into my lap.

"Time for stagecraft, little hound," I murmured.

I opened the hatch on Pipu’s underbelly and slotted a cold-vapor cartridge into his internal chamber. The cartridge was charged with compressed menthol steam and fine quartz dust, normally reserved for small parlor tricks where I made ghostly butterflies flit over patrons' cups. Above the cartridge, I clicked a faceted ruby scatter-prism into his collar bracket, angling the optical plane forty-five degrees to the right.

I set Pipu down on the wet grass near the ditch.

"Reeds," I whispered, tapping his brass ear twice. "Three paces beyond the willow trunk. Release on the bell."

Pipu’s internal escapement whirred into a stealth gear, deadening the strike of his brass paws. He slipped into the thick reeds without splashing a single drop of water.

I waited, my fingers resting on Kishi's damp nose to keep the old mule still. Ten seconds passed. The sentry blew on his slow match, sending a tiny shower of sparks drifting into the fog.

From the willow grove thirty paces to the sentry's right, a sharp hiss broke the stillness.

A thick burst of crimson-tinted vapor billowed through the drooping branches. Within the swirling red cloud, the scatter-prism caught the sentry's lantern light, refracting the mist into the crisp silhouette of an armored skirmisher crouching behind a log. On Pipu's back, a tiny flint-wheel scraped against steel with a sharp, metallic click—the unmistakable sound of a heavy military wheel-lock being cocked.

The sentry stiffened. He spun away from the bridge, his matchlock dropping to his shoulder.

"Halt!" the soldier barked, boots clattering against the bridge timbers as he stepped forward. "Who's in the brush? State your colors!"

The red shadow among the willows shifted, leaning forward with menacing stillness. Pipu struck his internal flint a second time, a loud, threatening snap that sounded precisely like a scout taking aim.

"Skirmishers!" the sentry shouted, his voice cracking with sudden panic. "Iron Duke's scouts on the western bank!"

The soldier did not wait to investigate alone. He turned and sprinted off the north side of the bridge, racing toward the green to raise the alarm.

"Now, Kishi," I hissed.

I urged the mule forward. Kishi broke into a brisk trot, his hooves thudding across the approach. I jumped down, dragged the spiked hemp barrier out of the rutted tracks, and threw it into the grass. The Gilded Moth rolled onto the bridge, her wooden wheels rumbling across the muffled timber planks.

Halfway across the span, a small brass shape bounded out of the reeds and leaped into the open wagon bed. Pipu landed with a satisfied thump, his cold tail spring wagging back and forth against the wooden floorboards.

We cleared the bridge and hit the southern towpath. The canal road stretched ahead through the river fog, flanked by rows of silver willows. Behind us, the church bell of Omu-Adu began to toll, a clanging alarm echoing off the brick locks.

Then, beneath the ringing of the bell, another sound rolled through the damp air.

It was a low, heavy thrum that vibrated through the wagon’s ash-wood frame and up into the soles of my boots. Far to the north, the rhythmic rumble of iron-tired caissons and marching boots trembled through the earth. Duke Oluwaseyi's main vanguard had accelerated their march.

I slapped the reins against Kishi's back, and The Gilded Moth plunged southward into the gray mist.