Art by: Chris Rahn

Even from three caverns away, the shriek of breaking metal echoed against the stone. Yet another broken excavator. If Karn had been an organic being, he would have sighed. Instead, he only paused and listened to the excavator's lingering rattles. He pitied his machines: no single setting could accommodate the eccentric geology of the Caves of Koilos, where olivine rock was as likely to back into sandstone as cinnabar, but he had no alternative. Here, he'd find the secret to operating the sylex.

And he'd find it before any Phyrexian agent could.

Condensation beaded on his body, the droplets joining to slide down his metal plating. No one seemed to believe him, but he knew the truth. The Phyrexians were here, on Dominaria. He could feel it, like he could feel the stone and the interplanar technology riddling its layers.

He turned sideways to squeeze through a narrow passage. The basalt grated against his chest but gave way without scratching him. He ducked under translucent stalagmites into a low cave. Clear selenite coated the bones of Thran prisoners and fragmented Thran technologies, their gold traceries distorted.

Karn located the failed excavator to the rear of the cave.

The poor excavator steamed, as if vexed with its unmanageable job, and its overheated metal housing ticked with a soft tink-tink-tink as it cooled. Karn wove between the stalactites and water pools, careful not to break any of the delicate violet mineral deposits or disturb the freshwater anemones and tiny blind fish, bleached by a life that had, until now, passed in darkness.

Karn placed his hand on the excavator. "Shall I fix you, then? Yes?"

Steam sighed from the overheated machine. At his gesture, screws unwound themselves along their threading. He set them aside and removed the housing. A stripped-out gear greeted him. He removed it and set to generating a replacement. His fingers tingled with magic, its charge pulling together to generate something from nothing. Metal materialized, layer upon layer, to create a duplicate part.

He liked working in the caves' silence. In the sun's absence, only the water's metronome drip measured out his days. He was alone here; other Planeswalkers didn't like the interplanar distortion that rubbed at their senses in the Caves of Koilos. Karn didn't either, but he appreciated the isolation it gave him. He didn't have to answer questions. Or worry about whether the Phyrexians had gotten to someone. Compleated them. He could seek the key to operating the sylex in solitude. He would win the fight alone.

"What fight?" Jhoira had placed her hands on her hips in exasperation. "Karn, the Phyrexians were defeated centuries ago, and these new ones you told me about are trapped on their plane."

"They're here," Karn had told her. "Defeating the Phyrexians in combat means nothing. They aren't an army. They're hate embodied. They promise Dominaria's destruction."

Her voice had softened. "Just because Venser . . ."

Karn didn't want to think about Venser. He slipped the gear onto its shaft and tightened it down. He replaced the housing, sliding it into place, and then threaded in each screw. Small pleasures. He patted the excavator and smiled. "That's better, isn't it?"

He knew it wasn't alive, wasn't responding to him, but it almost felt like it was as he flipped a lever and watched the excavator move forward and begin digging into the cave wall. The stone shuddered. Fine white dust plumed away from the excavator's planed shovel-limbs. If organic beings had been present, Karn would have had to worry about using water to damp down the dust. Their lungs were so fragile.

Better that he was alone, wasn't it? No one held him back, eating and sleeping hours away. No one delayed his progress with chitchat.

The pulverized rock turned violet, then the excavator's rumble changed to a whine as it hit open air. The excavator stepped back, and Karn peered into the cavern it had opened.

The rock had been thin as an eggshell but extremely hard. On the other side, the cavern's interior was coated in opal. The glow from his eyes caught on the iridescent flecks, suffusing the cavern with an amber glimmer. The dust-coated workshop looked like it came from Urza's mortal lifetime, or even prior, when magic's theories and practices were less well known, and technology propelled Dominaria's progress forward. Intricate glass tubing, beakers of varying sizes, defunct burners, powdery remnants of ancient chemicals, wire cutters and rollers for clay, buckets coated with desiccated glazes, gears, and cogs—even a small, vented forge, tongs placed casually to one side as if its smith, interrupted, had walked away from a task undone. In one corner, shackles: a reminder that the Caves of Koilos once housed the ugliness of the Thran before it transformed into Phyrexia.

This workshop had been some artificer's sanctuary—and some prisoner's nightmare. Karn recognized a setup meant to exploit sentient beings for experimentation when he saw one. He'd seen too many such scenes when he'd been newly formed.

"How did all this survive so intact?" If only he could share this sight with someone—

He really had to stop talking to himself.

Karn stepped into the cavern as lightly as his heavy body permitted. What if a stray vibration caused these delicate objects to shatter, destroying data?

The books, arranged on a single long shelf with jewel-covered spines, tempted him with their knowledge, but he dared not take one down. The paper would probably crumble into dust should he touch it. He peeked into the beakers, tinted with dried-out fluids, and then examined the forge's ashes. Nothing. He examined the pottery worktop and saw it: a diagram of the sylex painted on parchment, a coppery bowl with handles and small black figures marching around its base. A gray slab of clay sat next to the diagram, etched with symbols duplicating those depicted in the diagram's faded paint. Some were in Thran; some in the arcing curves of an unrecognizable script that resembled some symbols on the sylex. The clay was damaged, partially illegible, and severed wires lay beside it. What had happened here?

"I must compare this to the sylex."

At the faint vibration of his words, the books collapsed into dust. Karn winced.

He gathered the unfired clay tablet into his hands—careful, careful—and eased out from the ancient workshop.

Karn had sited his basecamp some distance from the excavators, where the caves had greater stability. Each softly lit tent sheltered his equipment from the steady drip of water. Karn let their brightness guide his steps, the hollow cavern booming with his footfalls.

With the tents lit from within, coming back to camp almost felt like coming home. Karn ducked into the largest tent, stepping around the large, golden Thran artifact he'd left in front of the entrance. Inside, he shimmied past a broken piece of metal he had collected days ago, intending to reshape it back to usefulness. He stepped over a pile of powerstone shards and sat at his work desk; it, like the rest of his tent, was too cluttered—he had no space for his newest find. Atop the papers and small artifacts, he saw Jhoira's letters, scattered, opened but unanswered. Karn, it's been months, one letter began. Don't you think you should examine why you're doing this? Another letter ended. Mirrodin wasn't your fault, she wrote in another. Please come back. Venser would have . . .

Art by: Jarel Threat

Karn shifted the artifact onto one palm and used the other hand to shove Jhoira's letters to one side. He slid the artifact onto the worktop then ducked under the table. He'd concealed the sylex in a small titanium chest, its lock only accessible to someone like him, someone who both knew the order in which the tumblers and pins needed to be lifted and could manipulate inorganic materials. His lock had no key.

He placed his hand on the chest, focused, and felt the tumblers move. The lid popped open. He removed the sylex. Even his specialized senses could not identify its copper-like material. Normally he could reveal any inorganic object's mystery with a touch; not so the sylex. It made his palms itch with its strangeness. A Thran artifact, most said—but he had his doubts. It was Karn's belief that this device came from farther fields than simply the past.

He lifted its wide goblet body onto his desk. Its inky characters seemed to move under his worktop's light, transforming from Thran to Fallaji to Sumifan. The vessel's wide, bowl-like mouth seemed to call to be filled—with, according to the Sumifan, the memories of the land. He'd been reluctant to test it without confirmation on how to use it.

The sylex sent a jolt through him. Karn flinched and withdrew his hand, cradling it against his body.

Once, when he'd been new, he'd reached out and touched the fire blazing in Urza's hearth. He'd dropped the cherry-red coal, shocked by the sensation, then examined his hand for damage. He'd found none. He'd looked up to see Urza watching him with glittering eyes. Urza hadn't tried to stop him, yet he'd known this would hurt Karn. Why did you give me intelligence if you do not value my personhood? Karn had felt ashamed the moment he'd asked the question, and yes, Urza had chuckled. You're more valuable to me if you can react intelligently. Karn had stared at his aching, undamaged hand. Then why give me pain? Urza had smiled and stroked his white beard. Karn had later learned how to recognize that expression as one Urza made when he thought he was being particularly clever. People are more reluctant to damage something if it causes that thing pain.

But that was only true of some people, wasn't it?

Karn glanced at Jhoira's unanswered letters. He did not dare involve Jhoira or the other Planeswalkers, lest he lose them to the Phyrexians like he'd lost Venser. Even after Memnarch renamed it, Karn still thought of that plane by its first name: Argentum. It had been Argentum to him when he'd created it and its smallest wonders. How beautiful it had been, a plane glimmering with mathematical precision.

The Phyrexians had taken it from him. His plane, his children. Memnarch, his creation.

And it was all his fault.

He grabbed a rag from a nearby pile to wipe the condensation from his body—he didn't want to drip on his new, unfired find—and dropped the rag back into the heap. He bent to study the sylex, comparing its symbols to those on the clay tablet. The pattern changed right where the clay tablet's edge seemed rougher. Broken. Had he forgotten a piece?

He needed to go back for it. Now. Since he'd opened the cavern to the caves' moisture, the artifacts in it would degrade.

Just then, the death rattle of another excavator echoed through the caverns. Karn wished he could sigh. But, as it was, he locked away the sylex and his most recent find. He'd repair the excavator—it was located near the ancient workshop anyway—and then he'd look for the missing piece.

Oily smoke oozed up from the excavator's housing. It seemed to have hit a hard mineral deposit, stressing the mechanisms behind the cutting tools. Karn patted it. "More than you could cope with?"

The machine released a gout of smoke.

"I know the feeling," Karn replied.

Before getting started, he peered around the tunnel's edge. The nearby workshop, despite the excavator's rumblings, seemed intact. Good. The excavator could continue its work without risking damage to those artifacts, then. After he repaired it, he would search the workshop for the missing piece to the clay tablet.

He pulled the machine away and reached into the wall where it was digging.

He scooped out something . . . liquid. Oily black slop dripped down his fingers, spattering the ground. Could it be . . . ?

Karn reached with his special senses into the material. For him—he had tried to explain it to Jhoira once—this ability was akin to tasting, if tasting were to provide information beyond flavor. He felt nothing. As if this substance was organic.

How had the cables been embedded into stone? It looked almost like they'd woven themselves into it, like worms through an apple that was otherwise undisturbed.

He had been right: the oil was Phyrexian. He checked again—could these fibers be ancient remnants? "No, no," he murmured. "They look recent. Fresh."

Karn reached into the borehole and grabbed one of the fibers. It writhed under his fingers, resistant, and released small spider-like clamps from its body to grip the stone. The cable was alive. He frowned. It lashed his fingertips as if trying to wriggle free from his grip. He tugged hard and tore it free from its tunneled cavity.

Black oil spattered across his torso from its root. The other cables contracted within the wall—and the ceiling to the ancient workshop thundered to the ground. The tunnel behind Karn crumpled, the passage to his basecamp gone.

He had lost his findings.

He would never locate the shard of the unfired tablet. He would never slot it in and see what it revealed. He would never fully investigate the chamber and determine if it housed other secrets about the sylex's creation. This recent development had seen to that. Now he had a more urgent problem, one he needed to prioritize over archeological catastrophe: the Phyrexians were on Dominaria. Here, now.

He could try to excavate the workshop. He could dig out the passage and return to his basecamp. He could reach out to the others, but seeking help took time and, Karn knew, put others at risk. If he had learned anything during his long life, it was this: a single moment of inattention, of neglect, could leave an entire plane vulnerable to the Phyrexians. The Phyrexians were contained within the caves for now, and he with them. Good. He would not let Dominaria fall like Mirrodin once fell. He'd stop the Phyrexians. If he could not do that, he would obtain proof enough that he could recruit reinforcements. Proof enough that Jhoira, and his fellow Planeswalkers, would believe him.

Karn, Jhoira would say, you were right all along.

Karn had only one direction he could go: forward. He stepped into the open Phyrexian tunnel. The walls looked organic, winding through the stone like veins through a body.

He followed the tunnel until it opened into a junction. Here, the walls had been carved into a frieze. Unlike the materials he had seen in the workshop and embedded behind translucent stone, these cuts seemed crisp and new. It had the vaulted quality Karn associated with religious practices, such as the stained-glass murals in Serra's temples.

In the frieze, a Phyrexian demon grasped a young human woman. The demon's elongated skull, bared teeth, and small eyes were depicted with loving detail. Each node of machinery and every exposed muscle fiber was polished until it gleamed. Small diamonds had been inset as highlights so that the demon seemed to move and glitter under Karn's gaze. In contrast, the human's profile, cut into the stone, was rough, her features drawn down into torment, revulsion, and fear. She held hands with another figure whose visage had been carved then intentionally defaced.

Art by: Volkan Baga

A whisper of cloth brushing stone drew Karn's attention. He turned, hand still pressed to the mural.

Humans always seemed so little to Karn. Only the tallest neared his height; all others were petite compared to him. These two—a man and a woman—were both small. The woman, her pale skin starved for sunlight and her brown hair ragged, had replaced her jaw with a hinged mechanism, small blades installed alongside her natural teeth. Where flesh joined metal, her scabs wept a sick, yellowish fluid. Her older companion, a white man with graying brittle blond hair, must have incorporated his technology more artfully: his white shirt lay open to expose the artificial heart beating between his ribs, the portal into his body protected with a glassy material. He had also added extra digits to his hands.

Both held chisels and large mallets. The sculptors, then. Acolytes from the Society of Mishra if their robes told him the truth. The female looked at Karn, then to his hand resting on the frieze, and shrieked in outrage. She launched herself forward. Her male companion followed her a second later.

She took a swing at his torso with the hammer. Karn seized her arm with one hand, and she drove her chisel toward the intricate, mobile plates along his abdomen. He grabbed her other arm. She grunted, straining against him. Her companion ran at Karn, raising his hammer over his shoulder. Karn swung the woman into her companion, slamming both into the wall. They fell in a tangle of limbs—nothing broken, just stunned—to the ground.

Karn bent over them and arranged their limbs. He held out his hands and generated restraints so that they could not attack him again. Iron particles buzzed at his fingertips, drawn from the aether. He called forth the metal in layers, building the restraints into bands on their arms and legs. He did not generate keyholes or a key, for he had no need to. The metal bands were solid.

The man moaned. The woman had enough fury in her to spit at Karn. The gob landed near his foot. They were so tiny. His strength, his reflexes, the facts of his body seemed an unfair advantage. Karn had torn through so many such creatures at Urza's request, walking through rank upon rank of soldiers like a lead weight through wet paper. He could almost feel it now: the resistance, then give, of those bodies; the heat of their blood trickling into his joints. The long hours he had spent while Urza slept cleaning his body with small wire brushes, scraping off the dried gore, digging out the clots from behind his knees. He had never felt clean enough.

"You are not Phyrexian," Karn said, "yet you are here, and if I am not mistaken, in service to them. What do you hope to accomplish?"

"You—you empty, fleshless husk. You desecrate our holy work with your touch." The female acolyte's rage dulled to a glittering self-satisfaction. "Others will respond to the barrier being broken. Gix's blessings upon them—they will come. They will come."

Ah, yes, the network of wires in the walls. When he had broken through them, he had likely triggered an alarm. Perhaps these first acolytes had responded as if some animal or natural event had severed the cables, but when these two did not report back, the others would not make such a mistake. Karn reached toward the female's face and, with a twist of his fingers, generated a metal gag. The only reason she hadn't shouted for help—sounds would carry in these caverns—was that it hadn't yet occurred to her.

She glared at him, making muffled noises that sounded like curses.

He leaned over the male acolyte. "What are you doing here?"

The male blinked at Karn. His pupils had dilated to different sizes. He was concussed. His speech, as a result, slurred. "Karn. I know you. It's good that you came."

Karn frowned.

"The Whispering One has a plan for you." The acolyte beamed. "She grows stronger daily, and you will serve her. Sheoldred welcomes you! It's your destiny, Karn, to create for us. To help us. To become one of us."

Karn generated another gag so that this one, when he regained his senses, could not call for help. The acolyte accepted the gag—almost as if he appreciated it—with a beatific smile.

Karn stepped away.

How had Sheoldred survived crossing between planes? A question he would ponder later: for now, he had to find her, to end the Phyrexian invasion before it started. And he could do that alone. Better that he did, for he could not be subverted. Venser's spark saved him from that.

Karn left the acolytes bound and gagged and plunged deeper into the cave network. The damp in these passages did not feel like the air around his camp but rather warm as breath. Hot moist air condensed on his cold body, trickling down in rivulets like sweat. Faint screams reverberated through the air.

The tunnel opened into a vast cavern, which echoed with the cacophony of human misery. On the other side of the crevasse was the Phyrexian staging ground, located on a broad flat area of the cavern floor. Antlike workers scrambled across the rope bridges strung over the crevasse, ferrying meaty gobs, bloody cables, and chunks of flesh over to humans being compleated on surgical tables. On the opposite wall of the cavern, a Phyrexian portal ship cut through the darkness like an immense scythe. Coils hung from this structure. The twitching loops' membranous purple gleam reminded Karn of intestines.

Sheoldred hung suspended in this morass. She was still. Tubes fed reddish and milky substances into her black segmented body. The mandibles that extended down from her thorax lay open, relaxed. Her humanoid torso, welded to the thorax's top, lay nested in a thick network of writhing inky lines. A horned mask obscured her face. Beneath her, worshippers clung together and raised their voices in an ecstatic paean.

The defunct Phyrexian portal ship and Sheoldred's sleeping form dominated the cavern. Acolytes in the gray robes of the Society of Mishra attended surgical machines that converted struggling people into Phyrexian abominations. Compleated monstrosities dotted the cavern's floor like grotesque artworks, skittering on too many limbs. More acolytes stacked weapons beside a Phyrexian skyship. Teams of splicers scaled a dragon engine to repair it, so small that their welding torches seemed like white stars against the engine's metal skeleton.

He'd found the staging ground of the Phyrexian invasion.

A single figure attended Sheoldred: a young woman with platinum-brown skin and dark umber curls who wore the cloak of the Tolarian academy. When she turned, Karn saw the red dot from a mechanical eye. Below, an acolyte hurried forward and offered up gobbets of flesh. The young woman sorted through them, twisting some into the morass that supported Sheoldred. Karn traced the line of acolytes carrying materials from the immense monstrosity to Sheoldred and her helper. She was mining the monstrosity to repair Sheoldred's damaged biological components.

If the other Planeswalkers could see this now, they'd know that Karn's fears were true. Jhoira would say—

No. It didn't matter what Jhoira would say. Karn faced this threat alone. He needed to alert the others, yes, but neither could he leave this staging ground intact. He had to destroy the Phyrexians before they could defend themselves.

His course of action decided, Karn held out his hand, palm up. He raised his other hand above it. He visualized the incendiary device he planned to generate from the inside out. He could see its every component, its chemicals, laid out like a dimensional blueprint. His fingertips buzzed with the magic of his creation. The layers of material accumulated in midair. It was no sylex, but it would end Sheoldred.

A klaxon filled the cavern with its high-pitched holler.

Karn located its source as acolytes, worshippers, and Phyrexian agents paused in their work: the female acolyte who'd attacked him was blowing a horn. Either she'd been discovered and freed, or she'd freed herself: the drawback to leaving his attackers alive.

The shrill sound prompted action. Acolytes loaded weapons into the skyships. Phyrexian surgeons loaded their bloodied operating tables into skyships. Others boarded the skyships, evacuating. Compleated Phyrexian monstrosities shuddered to life, metal fibers snaking out from their bodies. Others slumped to the floor. Claw-like limbs exploded from their abdomens and their gaping mouths opened blindly, like reptiles scenting for prey.

A red beam dotted Karn's chest.

Karn dropped flat to the rock just as a bolt of electricity flew overhead. He pressed his palms to the ground, lifting himself high enough to crawl forward. At the cliff's edge, he peered to the cavern's floor, trying to locate the blast's origin.

The Tolarian who aided Sheoldred leveled a glaive at him. She had replaced her eye with a miniaturized ray cannon, and its red beam hit Karn. Karn rolled to the side. A crackle exploded the rock beside him. Smoke wisped up from where he'd once lain.

Compleated Phyrexians swarmed toward him, and the Tolarian smiled. She placed a hand on Sheoldred's limp claw. Sheoldred remained limp, inert—as if she were under sedation while the young woman worked to restore her—and vulnerable.

And Karn still held his incendiary device.

The nearest bridge over to Sheoldred was close but narrow. Twelve ecstatic worshippers and the young woman with the glaive blocked his access to the Praetor. But Sheoldred seemed some distance from the Phyrexians and Tolarian acolytes located on the cavern floor. If Karn was quick, he would not have to battle through all Sheoldred's followers to attack her: just the twelve worshippers, the Tolarian making it thirteen.

Karn pushed himself to his feet and charged down the narrow stone bridge. Sheoldred's worshippers ceased their paean and launched themselves toward him. Two reached the bridge. Karn shouldered them aside into crevasse's abyss.

The other worshippers crowded themselves into a blockade. Two had leveled spears at him, which would have kept him at bay had he been a creature with flesh. Puncturing weapons annoyed him only if the shafts or blades became trapped in his joints and inhibited his range of motion. Similarly, the two young men with rotating saws did not give him pause: those blades would glance from his body. No, Karn focused on the worshippers who wielded the pistol chisels and welding torches.

It all came back to him so easily. He felt numb, efficient. As Urza made him. Karn stopped an inch away from the spearpoints. The worshippers shifted, uneasy. Karn took one step forward, seized a spear, and lifted. A worshipper, still clinging to his weapon, gaped and dangled. Karn swung him into foes, sweeping several off the bridge and breaking up their blockade. Then he tossed the spear-wielder into the crevasse's depths, the man's screams fading as he fell.

The other spear-wielder, an older woman, jammed her spearpoint into a gap in his torso. Although he held an incendiary device, he cracked the spear shaft by hammering his fist down, breaking it off inside himself. He'd deal with that later. He grabbed the broken shaft end, which she still held, and used it to swing her aside. She fell and crumpled.

Only six combatants remained.

The wielder of a rotating saw swung their buzzing instrument at Karn's head. Karn stepped back to evade. Before the saw could come around again, he stepped within the wielder's range and removed the tool from the man's fingers. The man tried to resist, but Karn had overwhelming strength on his side. Prying away the man's grip was disturbingly easy. Karn lifted him and tossed him into two more worshippers. The force crunched all three to the floor in a sickening confusion of broken limbs.

A piston chisel wielder rushed him from the side. The chisel thunked into Karn, then skidded down his arm, throwing its user off balance. Karn punched him. The man went flying. The remaining two worshippers fled; their faith was not so great in the face of such bodily harm. All these humans, even with the Phyrexian alterations, were no sturdier to him than butterflies. Karn wished it were not so easy.

He strode to Sheoldred. She hung, limp within her cradle but no longer quiescent. Her segmented limbs twitched like an arachnid's as she emerged into consciousness. Her human torso atop her thorax shivered. Her long fingers reached downward to the young woman in the Tolarian robes. But she did not seem aware—not yet.

"Karn." The Tolarian spoke with contempt. "I've heard a lot about you."

"How so?"

Her gaze flicked to Sheoldred's inert form, then returned to him. "You aren't as impressive as I've been led to believe."

Karn walked toward Sheoldred, the incendiary device in his hand.

"Who are you?" Karn asked the Tolarian. "Why would you bring this here?"

"Rona. And this," she gestured to Sheoldred, "is Dominaria's salvation."

Rona positioned herself between Karn and Sheoldred, glaive held easy and at an angle in her palms. Rona's flesh eye narrowed while her mechanical socket focused its laser onto Karn's torso. She flexed her hands around her glaive. Its blade brightened, crackling with blue electricity. She smiled.

"I do not wish to fight you," Karn told her.

"Too bad."

Rona leveled her glaive at him, and electricity burst from her blade.

The electricity danced across his body, sparking. Karn grimaced at the pain but pushed through it, walking toward her as more waves rippled from its blade, pouring over him. Karn paused, dazed, and tried to shake off the agony as Rona continued to attack. She swung the glaive down, lodging it into his shoulder. Karn twisted, pulling it from her grip, and removed it from his body. He threw it aside. While he was occupied, Rona unsheathed a dagger and jammed it into one of his abdominal seams. She dug it between the plates that allowed him to flex, as if searching for organs. Karn winced.

Karn gripped her head in one of his hands. He pressed his thumb into the mechanical eye and shattered the ray's lens. Rona shrieked and kicked. Karn tossed her into the wall. Bones crunched. She slammed into it, then fell to the ground. She curled, her hands around her head, her leg at an angle unnatural to human beings. Oil and blood oozed from the broken mechanical parts in her eye socket. She glared up at him from between her fingers, her lips drawn into a rictus.

"Why don't you kill me?" Rona taunted him. "Finish me off."

"I am not a weapon."

Karn neared Sheoldred, holding his incendiary device. Although her humanoid part was the size of an ordinary woman, she attached to a scorpion-like body easily three times his size. In contrast to that well-crafted beauty, the organic materials grafted into her human torso seemed crude, bloody. Rona had tried her best to replace the organic parts that had burned away in the Blind Eternities during Sheoldred's transit between planes, but its patchwork nature showed.

He would tear her to pieces. He would crush her while she was still weak. He would do anything—anything—to stop Sheoldred from Phyrexianizing this plane. Karn reached up and seized Sheoldred's torso, determined to finish this. He would tuck this device between the vulnerable plates of her body and destroy her.

At his touch, Sheoldred stirred. Her helmeted head craned down toward him. He could feel her with the same senses he used to determine the elemental composition of a compound. Her inorganic components stretched out before him like the pages in a book. Her biological parts lay like dark tumors nested within the metal's luminescent glory. He could read her thoughts—some of them.

Welcome, Father, Sheoldred whispered into his mind, one mechanical being to another. What plans I have for you.

Karn recoiled from her slimy whisper, stepping back. And he knew what she had done.

Phyrexian sleeper agents lurked in every land in Dominaria, these unknowing spies peppered throughout every government, throughout the military, throughout common people. He saw a brewer dumping hops into a vat. A spy. He saw a scribe sitting at a desk, her hand poised over a letter. He saw an adolescent playing chase with his cousins, pretending to be a monster when he was one, Phyrexian armature ready to explode from his back. Phyrexian agents were people's lovers, comrades, colleagues at work. They were everywhere. They could be anyone.

Welcome, her whisper echoed within him. Welcome.

Karn reached between the plates on her thorax and deposited the incendiary device inside her body. He lifted his thumb to flip the switch that would allow the two chemicals within it to flow into each other and combust.

But his hand did not move. His joints had locked. He attempted to look down to examine himself, but even his neck remained rigid. He tried to turn and couldn't move his arms, legs, or torso. He couldn't tell whether he'd been paralyzed or locked into place.

In his peripheral vision he could see Rona dragging herself—shattered lens, broken leg and all—toward unfamiliar magical devices, ones that she must have created herself. She left a trail of oil, blood, and fluorescent blue fluid behind her.

Karn strained against the strange magic that gripped him.

Rona levered herself up into a seated position. From her grunts, it sounded agonizing.

"Your mistake," she said, "was not killing me when you had the chance. We have expected your coming, Karn. We have prepared."

He tried again to move, his internal mechanisms groaning with the effort, and felt his metal torque. He would bend—break—before he freed himself from Rona's magic through force.

Rona sorted through the heaped parts she'd been using to repair Sheoldred. She lifted up a node, smiled, and set it aside. With a grimace, she dug her fingers into her damaged eye socket and yanked out the ruined node, exposing raw tissue and a piece of gleaming skull near her eyebrow. A gout of clear liquid spurted out. She clicked the new node into place.

Roars boomed through the cavern. Rock sifted down, pinging against Karn's body.

"That," Rona said, "was the sound of our ships evacuating our forces from this staging area—which has been compromised—and retreating to a secondary staging area. We have many bases across Dominaria. You will not find them all."

Rona drove her glaive into her leg. She grunted, slicing through her clothing and her flesh. Her eyes teared—even the eye she'd replaced dripped. Panting, she bared her muscle and her broken bone to the cavern's air.

Karn had failed. Held with Rona's magic, he would be unable to warn his friends, unable to fight at their sides, unable to save them when the compleated Phyrexian agents exploded from their dearest companions to kill them.

The cavern had emptied and quieted enough that Karn could hear the click as Rona slid a device into her leg. She sighed and folded her flesh over the metal. She fixed another panel over her thigh, sealing her wound shut, and then stood. She rolled her shoulders and smiled.

"Sheoldred, in her beauty, my Whispering One," Rona said, "grows stronger by the day, and she will lead us to victory."

Karn, still arm-deep in Sheoldred's torso, could feel clicking vibrate along his body. Sheoldred split apart, dividing herself up in pieces. Her segments broke away, each piece sprouting a dozen viridian segmented legs. The swarm poured over Karn, using him as a bridge to the floor. The spider-like creatures ran along Karn's arms, down his back and torso, the backs of his knees, his calves. The tink-tink-tink of their metallic claws reverberated through him. A tarantula-sized piece sprang free from the cables onto Karn's face. It clung to his head, twitching, a heart-like nugget of flesh grafted into the center of its modified thorax. It crawled over his head. He could feel its wet body slither down his back. It dropped to the floor and scampered away.

"I may not be able to stop you, Urza's creation," Rona said, "but I can prevent you from stopping us."

From the edge of his vision, Karn could see Rona limp down a tunnel. Even with her makeshift repairs, Rona remained heavily damaged, and she leaned on her glaive, using it as a cane. Her leg spurted yellow fluid, and she staggered. She paused to catch her breath. Oil dribbled from her new inserts, mingled with blood.

He turned his head to watch her. The field paralyzing Karn had weakened. Perhaps it was due to Rona's retreat. Did she carry the device with her that held him in place? Karn attempted to raise his arm. The effort shuddered through him. He lifted one finger.

Rona let her shoulder rest against the tunnel wall. She used her glaive to cut free a strip of cloth from her mantle. "I hope that as we take this plane, as we make it more perfect, you feel the keenness of failure once again."

Karn strained against the force gripping him. His jaw ached. "What . . ."

Rona bound the cloth strip around her leaking leg in a tourniquet. "As you watch the people you've known for eons transform and turn against you, I hope it hurts."

"Why would you say that?" Karn managed. He had to keep her talking. If he could break free . . . "What ­have I done to you that you would wish such horror upon me?"

"When the Mirrans became Phyrexian," Rona said, "it was the best thing that ever happened to them. They were independent from their creator. Unified. Beautiful."

The force holding Karn seemed to loosen. He needed to push free. Even with the Phyrexian staging ground in the Caves of Koilos empty, if Karn could capture Rona, as Sheoldred's right hand she would be able to provide valuable information. All was not yet lost.

"You'd kill them, wouldn't you," Rona said, "for reaching for perfection."

He only needed one more moment—

"You gave Memnarch your intelligence. Your capabilities. But he didn't have the experience to deal with it. The guidance. He was so lost." Rona's smile twisted. She enjoyed his struggle. "I can't stand bad parents."

Karn stopped. His body couldn't have reverberated more if she had struck him.

Rona flipped a switch on the wall. There was a small grating noise. Then, a series of booms overhead. The roar, as the cavern fell, engulfed him. Tons of rock poured onto him. A boulder rolled off the cavern's wall, then bounced into his chest. It tossed him onto his back. He stared up at the collapsing cavern, still paralyzed by Rona's device. Rocks sheeted down. Fist-sized pieces hammered into his body. Smaller pebbles thunked and plinked against him, rolling and filling in the gaps. His vision turned gray from dust then blackened out as the stone obscured all light. The rock weighed upon him.

He could feel Rona's spell ease. He could move—or at least beneath all this stone, he could attempt to move, to twitch a finger. For whatever good it did him. Not even he could lift this stone. Not even he could dig his way out from this cave-in.

The crushing layer of rock was too heavy even for him to shift.

Karn reached for the spark that allowed him to planeswalk. It burned within him, hot and bright, such a perpetual companion that he had ceased to notice it. If he could just focus and—

It didn't work. Nothing happened.

Karn reached out with his special senses through his fingertips and analyzed the surrounding inorganic materials: olivine, granite, quartz, mica. Ordinary stone, but with all the ancient interplanar and Phyrexian technology providing a low-grade interference, he could not planeswalk away.

He was trapped. Only he knew that Sheoldred had come to Dominaria, and he could warn no one.