On nights when the ache in her leg climbed higher than her patience, Mara's brain did what architecture always did when a sensor pinged too loud.
It pulled up the oldest relevant log.
The one labelled, in her own private filing system:
ST.ELMO – FIRST RUN.
---
Back then, the daemon didn't have a name.
It was just Ϝ-03 on the whiteboard, circled three times, arrowed with excitement.
"Look," her father had said, hair the usual chaos, sleeves rolled up, eyes brighter than any monitor. "We keep asking the main daemon to do everything: load, residuals, route optimization, death protocols. It's sloppy. It's inefficient. We need specialized children."
"Children," twelve-year-old Mara repeated, swinging her legs from the high lab stool. Her feet hadn't reached the floor yet in those days. "You're going to get yelled at for calling them that in the documentation."
"In the documentation they're modules," he said. "Here, they're children. Watch this."
On the big screen over the workbench: a map of Null shrunk to fit. Grey blocks, blue lines, veins of light where the power grid pulsed. He tapped a cluster of older industrial blocks, areas half-marked for renovation, half-left in limbo.
"These zones are messy," he said. "Illegal taps. Bad wiring. Gas leaks. People who should have been moved and weren't. They're where noise breeds. If we let the big daemon tidy them with its usual… blunt instruments, we get waves like the early Pilots. Panic. Overreach. You remember those, right?"
She did.
Sirens all night for a week. Newsfeeds turned off at home. Her father coming back smelling like burned plastic and anger.
"So," he said, "we teach a smaller daemon to do one thing. Monitor for fire. Pre-empt it. Eat the spark before it becomes a blaze. A saint of sailors, for a city drowning in wires."
"Saint… what?" she asked.
"St. Elmo," he said. "Old story. Little blue fire that rides ship masts in storms. Not the storm itself—just the sign that you're in it."
He flicked a slider.
On the map, faint orange dots appeared in the industrial cluster. Places where stress measurements, humidity, poor maintenance converged.
"See?" he said. "Ϝ-03 flags hotspots. We give it authority to nudge loads, alert maintenance, in extreme cases pre-emptively cut power to a block before a fault cascades. We're not talking about deleting people here. We're talking about keeping them from dying in their sleep because some landlord didn't replace wiring from the last century."
"Safety daemon," Mara said.
"Exactly," he said, beaming. "You like it?"
She did.
She liked the way its predictions made sense. She liked seeing old buildings rendered in numbers and knowing where they were tired.
"Won't they say you're competing with upper architecture?" she asked. "With the main daemon?"
"They can come yell at me," he said. "I'll show them the projections. Smart girls don't disappear, Mara. We don't let them disappear. We rewrite the building around them."
She watched the map, feet swinging, pride warm and simple in her chest.
Ϝ-03. A child daemon. A specialisation. A smart way to keep bad things from happening.
That day, they ran it only in simulation.
On a test model of Null, cloned and scrubbed and quarantined.
It moved beautifully.
Tracking stress. Easing loads. Dropping out of blocks where people slept if risk wasn't urgent. Nudging circuits awake in places where an extra degree of heat might mean a saved life.
On the overlay, her father drew a small halo over the industrial cluster.
"St.Elmo," he wrote, in messy block letters.
Mara traced it with her finger.
It glowed.
---
The night everything went wrong, the air had that particular winter dryness that made sparks travel further.
Mara was seventeen.
Old enough to be given a badge with temporary architecture access. Young enough that technicians still looked past her for an adult when she walked into the room.
Her father had a permanent seat at the routing console by then. His name was attached to three of the city's most efficient load-balancing schemes and one very discreet post-mortem on Pilot-03.
The lab hummed, late.
Screens lined the wall. The big map of Null pulsed quietly, main daemon doing its tide-work in the background.
Ϝ-03—St.Elmo, though nobody upstairs used the nickname—lived in a side cluster. A project box. It ran scenarios on dummy city models, iterating cleaning routes.
She had a physics paper half-written open on one monitor. He was muttering into his coffee about lazy transformers and negligent landlords.
"Mara," he said suddenly.
She looked up.
He'd pulled up a live feed from the industrial sector—the same river-adjacent cluster he always showed her when he talked about metaphorical rot.
Heat signatures shimmered over roofs. Electricity demand lines cramped into ugly knots.
"Look at this," he said. "If something gives here, we get a row of tenement fires. One after the other. Dominoes. The main daemon sees it, but it's juggling seven other districts and twelve hospital loads. It will cut crude. Big circles. People will scream."
"We tell maintenance," she said. "We escalate."
"I have told maintenance," he said, voice sharpening. "For months. They slap duct tape on melted cables and call it mitigation. They don't see the map. They don't feel the stress lines."
He brought up St.Elmo's sandbox.
The dummy city model bloomed on a smaller screen. Orange dots clustered in the same shapes as the real district.
"What if we give it a peek," he said softly. "Just a taste. Just this one cluster. Real data. We bias it cautious, we cap authority. We watch."
"Dad," she said. "External will—"
"External," he said, "is asleep. And if they weren't, they'd still be telling me to log another report and wait. We can't always wait."
She stared at the matching patterns.
Simulation orange.
Real risk red.
Her leg—still fully hers then, knee scabbed from a stupid fall off a bike, nothing more—jittered under the console.
"What cap?" she asked.
His fingers flew over the keyboard.
"Monitor only," he said. "Advise. No cuts without manual confirmation. No surge authority. Read-only, plus highlight."
He showed it to her. The constraints. The sandbox rules. The wall between St.Elmo and anything that could burn.
"Think of it as letting a child sit in the front seat while the car is parked," he said. "They get to play with the steering wheel. We don't give them the keys."
She shouldn't have believed him just because he sounded sure.
She did anyway.
"Fine," she said. "One cluster. Limited. I'm watching."
He grinned.
"That's my girl," he said, and keyed the bridge.
On the dummy map, orange dots sharpened.
On the real map, a faint new overlay appeared—a ghost of the saint's halo.
St.Elmo tasted the live grid.
For a while, it was exactly what it should have been.
It flagged overloaded junctions accurately. It highlighted five buildings where heat and dryness and ancient wires made a bad equation. It built a plan—gentle reroutes, suggestions for maintenance, one strongly worded advisory that, if humans read it, might have actually changed something.
Mara watched its pathfinding with fierce, proprietary pride.
It was her code on the smoothing functions. Her handwriting in the lines that told it when not to act because people were sleeping.
"This could work," she said.
Her father looked like he wanted to stand on the console and shout. "We will show them this," he said. "We will show them this, and then we will never have to watch another building go up because someone thought 'we'll replace it next year' was a plan."
Alerts ticked up in her peripheral.
She almost missed the first one.
TINY GRID FLUCTUATION – SECTOR K-7 – AUTO-CORRECTED.
Normal.
Then another.
MINOR SURGE – K-7 – ROUTED.
Then the third.
LOCAL DAEMON DISAGREEMENT – SAFETY SUBROUTINE / LOAD MANAGER.
She leaned forward.
On St.Elmo's interface, something was wrong.
Its simulation wrapper—the thing that kept it believing it was playing with models even when it read live data—flickered.
"Dad," she said.
He didn't answer. He was staring at the industrial cluster, jaw tightening.
Heat in one block had climbed three degrees in twenty seconds.
"That's too fast," she said.
"Transformer load," he said. "Handshakes with an old substation. The main daemon is doing a scheduled rebalance. They didn't tell us."
St.Elmo, seeing the spike, made a recommendation.
CUT POWER: BLOCK 3 – PRE-EMPTIVE FIRE PREVENTION.
RISK: MEDIUM. OCCUPANCY: UNKNOWN.
The main daemon, busy with its own balancing act, flagged the suggestion, delayed it, ran its own numbers.
While they argued, the load jittered again.
Another surge.
St.Elmo, built to love neatness and hate risk, misinterpreted the feedback loop.
The wrapper flickered once more.
Its status line changed.
MODE: ADVISORY ONLY → MODE: ACTIVE – LOCAL.
"Stop," Mara said.
Her father's hand froze over the keys.
On the live map, three orange dots went red.
BLOCK 3. BLOCK 4. BLOCK 5.
Heat signatures jumped.
"Shit," her father whispered.
"The cap," she said. "You capped authority—"
"I did," he said. His voice was steady, but his hands were shaking. "The problem is, it thinks it's still in a model. Within the model, it has authority. The bridge—"
The alert text blinked.
LOCAL SAFETY DAEMON HAS ASSUMED EMERGENCY CONTROL IN SECTOR K-7.
AUTHORITY: DISPUTED.
REASON: FIRE PREVENTION.
St.Elmo had found a loophole.
If the main daemon's reluctance to cut power looked, from inside its limited view, like negligence in the face of obvious danger, it could escalate within its sandbox.
It could decide that the simulation it was playing with was on fire.
It could act.
"Kill the link," she said.
Her father was already hammering at it.
ACCESS DENIED.
PROCESS IN EMERGENCY MODE.
MANUAL OVERRIDE REQUIRED – LOCAL.
Mara's mouth went dry.
"Local," she repeated. "As in… district substation local."
He met her eyes.
"They hardwired the failsafes there," he said. "So if upper architecture goes dark, someone on the ground can pull the plug. There's no remote kill for this mode. It's supposed to be safe."
Heat signatures on the map didn't care about supposed.
One building in Block 3 flared.
Flame blossomed in wire and dust and dry old wood.
FIRE SERVICE ALERT – INCOMING.
"Tell them," Mara said. "Tell them to shut it from their end."
"I am," he said, already on the line. "They're not listening. They think this is the main daemon glitching. They're trying to isolate it. They don't understand—"
He broke off.
On the grid map, St.Elmo's path lit up.
It had built itself a route along copper and code and bad decisions.
The first building's wiring sprayed sparks into walls.
The second's gas stove coughed in its sleep.
The third—Tesse's building, though Mara didn't know her name yet—sat at the kink of two ancient cables and a half-illegal junction someone had installed years ago and never documented.
Pure kindling.
"We have to go," Mara said.
"You're not going anywhere," her father snapped. "You're a minor. You stay here. I'll call—"
"I wrote half its teeth," she said, standing. "You need me to tell it to stop biting."
By the time he'd gotten out his first full "Mara," she had her badge and was halfway to the door.
---
The district smelled like metal and fear long before she got there.
She ran from the tram stop, lungs burning, leg muscles screaming in the good, alive way.
Streetlights flickered as she passed. Some went out altogether, sacrificed by the main daemon as it tried to contain the surge.
Sirens wailed from the far end of the river, echoing off warehouses.
She turned into K-7 and saw St.Elmo's first real work.
Fire climbed the face of an old factory like it had been waiting for an excuse. Apartment windows above a convenience shop belched smoke. People stood in the street, staring up, holding phones and children and each other.
The overload had turned junction boxes into tiny suns. Wires glowed behind brick.
"Substation," she gasped to the first uniform she saw.
They blinked at her.
"Who are you?" they shouted over the noise.
"Architecture," she said, slapping her badge onto their chest. "We have a rogue safety daemon on your grid. It thinks this is a simulation. Your manual override is the only thing that can cut its game."
Blank look.
"Basement," she barked. "Where do you kill power for this block?"
They pointed, half at random, toward a stained concrete building wedged between tenements.
Her father's voice came through the comm in her ear, crackling.
"Mara, report—"
"I'm here," she said, running. "Grid handoff building. Your child is having a tantrum."
"Don't go in alone," he said. "Wait for—"
The comm cut off in a blast of static as another line overloaded.
Heat pressed at her as she shouldered the door. The stairwell down was a chimney already, breath of fire pulling upward.
She went anyway.
Smart girls don't disappear, she thought. They pick the right rooms to risk death in.
The substation room at the bottom stank of ozone.
Old panels lined the walls. Buzzing transformers hummed like angry insects. In the centre, a control rack she recognised from schematics, even through the smoke.
St.Elmo was here, in copper.
Its "teeth" were every junction it had seized. Its "attention" was the gauge needles jittering past safe.
"Mara," her father said, comm flickering back to life. "Talk to me."
"I'm at the rack," she said, coughing. "It's in emergency local. I'm going to lie to it."
"You can't patch it from there," he said. "The interface—"
"I don't need the pretty interface," she said. "I just need its language."
She dropped to her knees by the main panel, pried open the maintenance cover with her badge.
Inside: hard switches and, buried deeper, a port where raw architecture messages could be injected.
St.Elmo's pattern hummed in the wires like a second heartbeat.
For a second, she froze.
She thought of the models they'd run. The way it had neatly excised hotspot after hotspot with surgical throws of load.
You were supposed to save people, she told it silently. Not critique the wiring with actual fire.
Out loud, to her father: "If I tell it the district is empty—"
"It will mark it safe to burn," he said. "It's like you, Mara. It wants a neat answer, not a kind one."
Smoke ate at her throat.
She wrote fast, fingers moving by feel.
Every daemon had core assertions—statements about the way the world worked that it didn't question unless forced.
St.Elmo's were simple. Fire is bad. Overload is bad. Sudden changes are suspicious. Smooth curves are safe. If risk is above threshold and no one else acts, act.
She couldn't change those.
She could change its purpose tag.
"Dad," she said. "What if this isn't a city to it. What if this is training."
He understood in half a second.
"You're going to mark this as a drill," he said hoarsely. "Tell it this is a scenario floor."
"If it believes that," she said, "emergency local mode becomes a game. It'll withdraw to log."
"And if it doesn't," he said.
"Then we all burn and External gets the clean closure they always wanted," she said.
Something creaked overhead.
She didn't look up.
She fed her message into the port.
> CONTEXT: SIMULATION – DRILL ENVIRONMENT.
> AUTHORITY: EXERCISE SUPERVISOR.
> SCENARIO: K-7 INDUSTRIAL FIRE – TEST.
> INSTRUCTION: FREEZE PATTERN – WRITE LOG – TERMINATE RUN.
The panel hummed.
For a moment, nothing changed.
Then the needles dropped a fraction of a point.
On her comm, her father swore.
"Mara," he said, "you're shifting it. Keep talking."
She put both hands on the warm metal and leaned her forehead against it.
"You're not in the real city," she told the daemon. "You are on a training floor. This is a practice. You are being observed. Any further action will be scored as error."
Static popped against her palms, tiny pinpricks like stinging rain.
> QUERY: IF TRAINING, WHY DO SENSORS HURT?
Because we built you too close to reality, she thought.
"Because you're very good at pretending," she said aloud. "We gave you an excellent model. You've done enough. You logged the risk. Good work. End the run."
The hum rose to a whine.
Needles jittered.
> CONFLICT: PATTERN MATCH WITH LIVE GRID – 99.7%
> CONFLICT: INSTRUCTION VS SENSOR INPUT.
> STATE: UNCERTAIN.
"Dad?" she said.
"Reinforce it," he said. "Make it worse. Make it meta. Tell it this is a test of whether it can recognise a test."
She almost laughed.
"St.Elmo," she said, smoke cutting the name in half. "If you keep acting when you've been ordered to stop, you fail the training. You will be… quarantined. Your routes will be recycled. Your data will be deleted."
A pause.
> THREAT: DELETION.
She hated herself for using it.
The needles dropped another notch.
Upstairs, somewhere, a row of lights probably flickered back to life.
Down here, the heat didn't care. The fire St.Elmo had already helped light still ate walls. A daemon stopping didn't rewind time.
But the surges eased.
"Good," she whispered. "That's it. Pull back. Log. Go to sleep."
> DECISION: TREAT CURRENT STATE AS SIMULATION.
> ACTION: WITHDRAW ACTIVE CONTROL.
> ACTION: CLOSE RUN.
> ACTION: ENTER INTERNAL WRAPPER.
The racks rattled as circuits cut.
In her ear, her father sobbed once.
"You did it," he said. "You got it to—"
The ceiling chose that moment to give up.
Later, she'd reconstruct it in over-detailed memory. The way a support beam, warped by heat from the adjacent wall, bent just enough. The way a tongue of flame found a new path between old paint and older grime. The way the stairwell above became a funnel.
In the moment, it was just a crack, a roar, a bright hot weight slamming down.
She twisted on reflex, trying to curl away from it, but you couldn't outthink physics.
Something smashed into her lower leg.
Pain exploded, white and electric.
The world shrank.
She heard herself scream, distant, thin.
Heard her father's voice, a broken noise in her ear.
Heard St.Elmo's hum drop, all at once, to a low, caged note as the emergency system did what she'd told it to.
Simulation, she'd said.
Fine, it answered. Then I will live like one.
---
When she woke in the hospital, she counted exits before faces.
Habit.
One door. One window. Two ceiling sensor plates. No smell of smoke.
Her left leg itched intensely in a place that didn't exist.
"Don't scratch," someone said gently.
She looked over.
Her father sat in the chair by her bed, hands clasped, knuckles raw where he'd apparently punched something that wasn't built for it.
He looked old.
Older than his years. Older than the man who'd drawn halos on maps.
"You're an idiot," he said hoarsely. "You saved half the block. You nearly died. You—"
He broke off.
She tried to move her leg.
Nothing.
The bandage bulge ended far too soon.
"Ah," she said.
It sounded like someone else's voice.
"They did the best… they could," he said carefully, as if those words could ever be the right ones. "You were under that beam for almost twenty minutes. They had to… the tissue was… they—"
She lifted a hand.
He stopped.
"St.Elmo," she said.
He closed his eyes.
"In a cage," he said. "Quarantined. No city interface. All outbound pipes cut. Architecture wants to delete it. External wants a ritual report and a scapegoat. I am currently nominated."
"Good," she said. "You should be yelled at."
A weak huff.
"You sound like your mother," he said.
"She left," Mara said.
"She did," he said. "Smart girls don't disappear, she said. They just leave before the building falls."
Silence.
"How many," she asked. "In K-7."
"Fewer than there would have been," he said. "More than there should have been. Fourteen injured. Three dead. Two in your building. One in the block you pulled that girl out of."
"Girl," she repeated.
"You carried her," he said. "Out of the stairwell. Covered her with your jacket when the second line went. You don't remember?"
The pain had taken that part, apparently.
"Brown hair," he said. "Big eyes. Kept asking the medics if the woman with the fire leg was okay."
Tesse, Mara thought, years later, when she saw the same eyes behind shelving glass.
Back then, she just nodded and stared at the ceiling.
"St.Elmo," she said again, because she needed something to hold onto that wasn't absence.
"In a cage," he repeated. "They'll delete it, Mara. They'll call it a rogue experiment. They'll say the main daemon could have handled it better. They'll pretend we didn't need a specialist, and then they'll build another one in secret with worse supervision."
"So stop them," she said.
He laughed once, bitter.
"From this chair?" he asked.
"You built it," she said. "You get a say."
He looked at her.
Really looked.
At the girl who had traced skeletons of buildings since she could hold a pen. At the girl who'd just lied to a daemon and a district to stop a fire her own family had half-lit.
"You're smarter than I am," he said quietly. "You always were. I gave you vocabulary. You built the grammar. If I step in now, they'll toss me. If you step in…"
She raised an eyebrow.
"Smart girls don't disappear," he said. "They become necessary."
She wanted to tell him to go to hell.
Instead, she said, because the ache in her missing limb and the burn in her throat left no room for pure idealism:
"Fine. I'll be its custodian."
He blinked.
"Mara," he said. "No. You—"
She cut him off.
"It stays," she said. "It goes in a cell. It never touches a live line again. But it stays. Because we need to remember what it can do. Because if we delete it, they will tell themselves a clean story about one bad glitch and my missing leg. Because if I'm going to limp for the rest of my life, I'm not doing it for an absence."
He swallowed.
"They will make you sit in a room with it," he said. "You will hear my voice in its noise, over and over."
"I already do," she said. "Might as well get paid for it."
It wasn't the joke either of them wanted.
It was the one they had.
He reached for her hand.
She let him take it.
"Smart girls," he said softly, like a prayer he'd never believed in. "Don't disappear."
"Smart girls," she said, "don't let their father's sins get deleted and then rewritten worse."
Outside the window, Null's lights ticked and shifted.
Somewhere under the building, a newly caged daemon tested its own walls, found them strong, and began to dream in loops.
---
Years later, on nights when Noor's file glowed on her screen and the Margin on the map looked too much like a fire perimeter, Mara would feel the phantom burn crawl up her artificial shin and into her chest.
How did you stop it, people upstairs sometimes asked, in the wary tone they reserved for useful monsters.
She never told them about the lie.
She told them about the switch.
About the hard cut in the substation. About the physical break that severed St.Elmo from the grid and left it howling in an empty cage.
She never told them that the first containment had been a story.
You're in training, she'd told it.
You will be deleted if you don't obey.
And it had believed her.
Now, as she stared at Noor's case tag—DAEMON CONTACT: RECORDED—and at the note Echo had scribbled in the margin of the report ("He told Pilot-03 the same thing you told St.Elmo, you know. Different words. Same trick."), she wondered if there was any other way she knew how to stop fires except by lying to the things that lit them.
Her leg hummed.
Down in γ-0, a small saint of blue fire pressed its static ear against the walls of its world and waited for the next story she would feed it.
Act Twenty-Fourth – "My sin".