The ruins predated the Magistracy by six centuries. Someone had placed the structures with considerable astronomical care. The exposed Nexus sat dead centre of the circular clearing, oriented to the north star within half a degree. Jagged stone jutted from the earth like broken teeth, fir trees ringing the perimeter so dense the mountain wind arrived in gusts rather than constantly.

The moon was enormous. Pink and swollen and very close. Its usual soft glow intensified to an almost painful brightness.

The air smelled of pine resin and the particular mineral sharpness unique to an active Nexus. To Dareth Oakenshield it smelled like good work.

He stood on a raised limestone block with his pocket watch in hand, survey log spread open in the other, dark velvet cloak billowing behind him in the wind. His blue eyes fixed on the moon while below him the Nexus lit his angular face in a cold hue, the cobalt light catching the same shade as his petticoat.

Fire sconces flickered atop sparsely placed tables, bathing the area in dancing light.

Today was Shiin's Day. Dareth noted the date primarily because the moon's proximity to the earth during Shiin's blood moon was integral to his hypothesis. He was never a man given to holiday sentiment. Or superstition, for that matter.

"Thirty seconds," he said.

Cornelius's substantial form stood at the barometer ten feet left, wire spectacles slightly fogged from the climb, walking cane forgotten down in their wagon. Wand at the ready, periwig askew showing bald skin below.

Around them the survey team held position. Lena at the astrolabe. Young Presswick at the instruments array, stylus hovering uncertainly. The Bluecoat escorts stood uselessly at the treeline, leaning over their halberds.

"Barometric pressure is dropping rapidly," called out Lena, eyes fixed on the brass instrument. "Down fifteen millibars and falling."

"As expected," Dareth mumbled, checked the timepiece briefly.

The shadow began its advance.

"Go ahead, Corn."

"Initiating sequence." Cornelius raised his wand and produced an illumination charm — basic, simplest in the canon.

Nothing.

Dareth jotted in his leather-bound journal: 0 hrs, 0 min — Illumination: null. Hypothesis holding.

Then the temperature dropped substantially, enough that Dareth's breath fogged in front of him.

"By the Nine," Cornelius said quietly.

Dareth pocketed his watch with a sharp snap and climbed down to the giant crystals. His hands found the glossy surface.

Cold. Completely inert. Not dormant — inert. The distinction felt significant and he filed it immediately.

"The energy's gone absent," he said. Lena came over with a candlestick, golden light flickering back against Dareth's stern face.

He tucked away the frilly sleeves hanging over his bookish hands and moved them carefully across the formation, finding something new.

"Structural changes — fissures forming along the growth axis. Hairline thin. Progressive."

Cornelius and Presswick's styluses worked frantically above.

"Sir, the moonstone samples have all gone black," Lena called out.

He paid her no mind. He checked the pocket watch again. Four minutes of darkness that seemed louder, more ominous than regular darkness. The Bluecoats made a sound from their posts — a faltering question left unheard by four mesmerised scholars.

Then the moon's edge reappeared. Magic and warmth returned with an almost audible snap. A pressure releasing, a door opening into a larger room. Cornelius lit his wand, laughing with relief. Dareth's own wand hummed in its pocket. Lena hurried back to the instruments. A Bluecoat exhaled.

Dareth didn't pull his eyes from the damaged Nexus. The fissures glowed — silver against black, much like his own long hair and trimmed beard. He rubbed his chin, whiskers rustling, and sighed as he contemplated the implications. For what it would mean for Cora. For the entire continent. Then he thought about his pipe and tobacco waiting in the wagon and pushed that thought away.

He pressed both hands flat and leaned in, and his fears were confirmed. The energy didn't terminate here. It ran — north and south and east — toward other points, connecting them. The primal rule of magic: magic sought magic. The coldness of the moon's absence had cracked the crystalline formations and a network was forming. All of it centred on Cora. The continent transformed into a body, Cora its heart, the magic its pulse.

Dareth reminded himself to write this allegory down first thing.

"Dareth?" Cornelius attempted from the safe balcony.

He snapped out of his thoughts, checked his watch, flicked it shut, adjusted his sleeves and tugged the cravat straight. With a sharp move he strode past the tables and lanterns and let his voice of deeper register carry.

"Log everything. Every instrument reading, every personal observation, sensation, every timestamp. Do not omit anything on grounds of seeming minor. What we've just witnessed is anything but."

Cornelius, his larger frame quite imposing in layered Magistracy garb and chains of rank, pinched his small glasses and looked to the small company, standing dumbstruck by the direct order from a man more comfortable in abstract theorems. "You heard him. Secure the moonstone. You two, prepare the tents. We have work to do."

The first correspondence arrived on the third morning while they were still cataloguing each mineral sample with the care Dareth had taught them all.

While Dareth was lecturing Presswick about precise extraction methods, a deep, croaking voice interrupted.

"Come here, come here."

A raven, black and beautiful as the deepest obsidian, plopped onto the wagon's roof, shimmering in the morning sunlight. Dareth recognised Hannah, Maester Rothwell's personal raven, by the emblem around her neck. Her head turned this way and that.

"Hannah," Dareth said curtly, stepping closer. "What news do you bring this time?"

"Come here, come here." She made a little sideways dance toward him. Dareth stroked her feathers once, felt warmth and bones beneath, and untied the scroll from her leg.

"Good girl."

Rothwell's careful handwriting greeted him, encrypted in the typical fashion of runes and codes. Dareth's mind deciphered it quickly without the assistance of a key. The colour left his face.

Changeling murder. Arable. Read the victim's mind. Capture, do not kill. No errors this time.

He read it twice. Secured it inside his breast pocket beside his pocket watch. His jaw worked.

Another Changeling murder. Arable. The order to read a dead mind — a violation of every ethical principle he held dear.

Cornelius was at his side before he'd thought to call him.

"Dareth, old chap. What is it."

Dareth recounted the message. Voice low but calm.

"Arable," Cornelius said, looking for clues in Dareth's face rather than the letter.

"Yes."

"Where Oskar Helmbane's family lives."

"His daughter and last wife, yes. And if I recall correctly, his sister maintains a residence in Greenlake nearby." Dareth looked at the crystal formation — silver-veined, humming with its new current. "Rather peculiar timing, wouldn't you agree, old Corn?"

"Very peculiar." He nodded solemnly, patting Hannah's back while she let out a low croak.

"The eclipse may have disrupted the Changeling's powers," Dareth said, mostly to organise his own thinking. "The Nexus disruption would have affected any magic drawing on it. If the victim's memory imprints survived, we might establish the Changeling's identity before it struck again." He paused, hand seeking his pocket watch for comfort. "What Rothwell is asking remains ethically indefensible regardless of the practical argument for it."

Before Cornelius had time to respond, Hannah moved to pick at Dareth's sleeve, her beak snapping. "Dead mice, dead mice," she croaked insistently, head bobbing.

Cornelius chuckled, shaking his head. "Hold on, Hannah. We've got something else for you." He lumbered away to the supply wagon and returned with a piece of sausage, tossing it to the raven, who caught it and set to work on it immediately.

"I intend to do it anyway," Dareth said. He moved to the wagon and selected vellum. His reply was four coded words.

Heading to Arable forthwith.

Three oak leaves pressed into blue wax. He rolled the message and tied it to Hannah's leg. She accepted it with a nod and departed in the direction of Cora without ceremony.

He ordered the small company to pack up and move south. Arable wasn't far — a day's trip by horse at best.

The wagon was a small replica of a Magistracy study —polished mahogany panels, brass lanterns swaying from hooks, leather-upholstered benches.

 Dareth withdrew his pipe. Meerschaum, acorn bowl, familiar in his hands as his own wand. Lit it with a minor charm and sat across from Cornelius as the wagon began its descent through the mountain pass.

Cornelius pulled away the periwig, letting his balding head breathe.

"Arable is a peculiar choice for a Changeling," Dareth mused. "Isolated. Magistracy-aligned farming colony. No obvious target." He drew on the pipe. "Unless—"

"Oskar's daughter?" Cornelius supplied, pulling out his writing kit and fresh paper from a compartment beside his head.

"Could she have inherited the sword after—" Dareth couldn't finish the sentence. Sucked harder on the pipe. Cornelius noticed.

"You mean it came for the Demon Slayer? The Beardaughter boy was its last owner, if my memory serves."

"Yes." Dareth said stiffly. "Oskar's last wish was for him to have it before he died, which was absurd given the circumstances at the time—"

Dareth looked out the window. Refused to finish that sentence. Refused to think of that freckled face. The dangling feet. He moved on, to safer territory, pipe warm in his hands.

"Let's say Oskar's daughter carries the Demon Slayer." Dareth tilted his head, watching the smoke flatten against the wagon's low ceiling. "A mithril blade of that provenance would be a considerable repellant to a Changeling operating at this level of sophistication."

"Indeed." Cornelius agreed and opened the survey log to a fresh page, taking note of Dareth's musings.

"Why?" Dareth asked the smoke-filled ceiling rather than his friend of eleven years. "Why would a monster choose to seek out the very thing that could destroy it?"

While Cornelius wrote, Dareth settled his pipe into the brass ashtray, picked up his quill, and resumed the theoretical framework for Nexus interconnection. Below his professional thinking, in the quieter register where he kept things he did not examine closely, he thought again of the golden boy from his youth, and of the faceless corpse awaiting him in Arable.

He noted it. Set it aside. Wrote.

The mountain pass fell away behind them and the road to Greenlake opened ahead, straight and cold and clear in the morning light.