Chapter 12: Fallback Vector

Rikka hated the smell of burned plastic, and it took her exactly zero seconds to decide she wasn't going to be sentimental about it, because sentimental was for people who got to grieve somewhere safe, and she didn't do that kind of weakness in public corridors, not today, maybe not ever, don't you dare start now, Rikka. What she actually hated, once she stripped the smell down to what it meant, was that someone had time. Time to get here first. Time to stand in her space and decide it deserved to be erased, and they hadn't even bothered stealing anything worth the trip, no wires pulled, no gear lifted, they'd just burned it, purely to make a point she was apparently supposed to receive.

Semireiya went first, because Semireiya always went first, one hand finding the service panel and the other finding the rail like her body had already rehearsed this exit a hundred times before her mind caught up, face doing that scary-calm thing, the kind of calm a knife had right before it did something a knife does. Usagi stuck close behind her, still trembling from whatever MITA's little door-speech had done to her insides, walking anyway, because walking anyway was apparently the whole trick to being brave when you didn't actually feel brave, and the proof strip sat in her pouch like it was a passport stamped for somewhere better than this.

Rikka went last. Not because someone had to, but because she didn't trust herself not to look back if she wasn't forced to keep moving. She looked back anyway. For half a second her node was exactly the way it used to be in her head, messy and stubborn and full of junk nobody else would have wanted, a tiny stupid claim staked in a city that wanted everybody to add up to nothing. Then she made herself look forward, because there was no save file for standing still.

"Okay," Rikka said, too bright, the way she got when the alternative was screaming. "Plan B. Everybody loves Plan B."

Nobody laughed. Semireiya didn't even blink at it, and Usagi's mouth did that thing where it almost tried, and the joke just sort of dropped and lay there on the floor between them, something Rikka would now have to step over for the rest of the walk.

A cadence started somewhere behind them, not the shutter tones, something underneath those, a slow repeating pulse riding the corridor infrastructure like the whole city had decided to hum through its own pipes just to remind them who owned the place. Rikka's stomach did the thing it did.

"That's the Hymn," she said, mostly to hear herself say it.

Semireiya nodded once. "Sweep is moving."

Usagi's antennae tipped forward, shivering. "It's close."

Of course it's close, Rikka thought, of course the second she got herself un-erased the city decided to tighten the leash again, story of her whole stupid existence, but she didn't say any of that out loud. She just swallowed it down where the bitterness usually lived and did the one thing she was actually good for.

She became useful.

Three ways out, and Rikka gave them each about half a second, because that was the going rate down here. One was clean, practically gift-wrapped, new conduits and none of the usual leaks, the kind of hallway that looked like it wanted you to use it. One had old utility panels and a drop ladder tucked away, nothing anyone would ever brag about. One was just ugly, uneven grating, a drain smell thick enough to have its own personality, the kind of path that made you want to hold your whole face away from it.

The clean one was the trap. Clean routes got watched. Rule one of every under-city job she'd ever half-finished.

She pointed at the ugly one. "We take that."

Usagi blinked. "That one smells..."

"Like survival," Rikka said, then dialed it down a notch when she caught Usagi's face. "Trust me. The city likes to watch the pretty paths."

Semireiya didn't argue, didn't ask her to justify it, just said, "Lead." One word, and it hit Rikka harder than the burned node had, because Semireiya, actual final-boss-tier Semireiya, had just handed her the wheel, and don't you dare crash this, Rikka, don't you dare. She almost laughed again, except this time it wasn't a joke trying to get out, it was something closer to panic climbing her own throat.

The drain route dropped them into a maze of maintenance channels that didn't match any map anyone official had ever drawn, floor slick in patches, walls plastered with warnings so faded nobody had listened to them in years, old cable bundles hanging low enough to clip a shoulder if you forgot to duck, which Rikka never forgot, because ducking was basically a reflex she'd built entirely out of past mistakes. She kept her steps light. She'd run guts like this before, not this exact route but the shape of it, because the under-city had patterns even when it was trying very hard to look like chaos, same as every level she'd ever cheesed.

Behind them the Hymn cadence swelled and thinned, swelled and thinned, hunting for pockets of movement the way a scanner hunted, and it wasn't a voice so much as a pressure that sat on the back of your neck and waited.

Her hand kept drifting toward the strip of tape still stuck to her glove, from the last time she'd tried and failed to peel MITA's stupid tag bead off her skin. The bead itself was gone. Whatever it had left behind probably wasn't, not really, she didn't understand the tech enough to know for sure, she only knew MITA had lobbed it at her like a joke, and the joke had grown teeth somewhere between then and now.

"Semireiya," Usagi said, low voice, "your pace..."

"I'm fine," Semireiya replied instantly.

Rikka heard the lie sitting right on top of the sentence, not because Semireiya sounded weak, she never sounded weak, but because she sounded too controlled, like she was holding her own skull together purely through discipline and would rather die than admit the effort. Rikka filed it and said nothing, because calling someone out at the wrong second could cost more than saying nothing ever would, and she was, against all evidence to the contrary, capable of picking her moments.

First fork. Left went wide, with an old service light doing its best flicker impression of a dying thing. Center was a straight chute with a thread of breeze running through it, which probably meant it hooked into something bigger somewhere down the line. Right dropped and narrowed and smelled worse, if that was even a category anymore. She took center, not because it was the safe pick, there wasn't a safe pick, but because it put distance between them and anything hunting faster than a bottleneck would, and she was allergic to bottlenecks on a level that probably counted as trauma. Semireiya followed without a single question. Usagi followed with that careful little half-step she used whenever she was trying to listen to every direction at once.

The Hymn cadence drifted off to the left behind them, not toward them, and something in Rikka's chest loosened half a notch, a small rare gift, a breath window she had zero intention of wasting.

They slipped through two more junctions and ducked under a busted camera housing that Rikka refused to even glance at, because looking up at dead eyes was basically announcing to the universe that you were scared of them, and she forced her brain back into the boring mechanical mode she used for exactly these moments. Left: a ladder drop into lower pipes. Right: a tight crawl with a handrail bolted on like an afterthought. Straight ahead: a door panel with a key slot that had absolutely no business existing down here. The door was too convenient, too polished, practically had a neon sign over it reading trap, so she took the ladder instead.

She grabbed the rail and swung herself over first, which wasn't heroics, just math: if this ladder decided to give out, better it happened under her than under either of them. Her boots hit the lower grating with a clang loud enough to make her wince, and she held up a hand. Safe. Semireiya came down next without a sound. Usagi followed, careful, fast, already reaching for the next thing to worry about.

Then something changed that had nothing to do with what she could see. The comms just died. Rikka knew that particular flavor of nothing, a dead pressure sitting where the ambient signal was supposed to be, like a limb gone numb except the limb was the inside of her own skull. The under-city wasn't ever quiet, not really, it was just, suddenly, disconnected.

Usagi's antennae twitched hard, then angled downward, cut off from the air itself.

"Dead-zone," Usagi said, barely audible.

Semireiya's gaze sharpened. "No contact. Hand signals."

Yeah, no kidding, Rikka thought, and for once kept it entirely to herself, just nodded and got moving again.

The dead-zone dragged them close together whether they liked it or not, no calling ahead, no catching distant chatter, no warning tone until whatever it was already standing on top of you, and Rikka hated that on a purely personal level, because it made the whole run come down to luck, and luck was the one mechanic in this entire stupid city she had never once trusted to be on her side.

They kept moving through the lower pipes, along a service loop Rikka half remembered from some job she'd taken years back, curling upward again through a string of narrow access points, the kind of place that never made it onto any public map because public maps liked to pretend the whole city was clean. She checked her corners out of habit, rail and cable cover doing the job of actual cover, while her brain kept sprinting ahead to whatever came next: MITA comes back. The Hymn finds us. Semireiya loses it completely. Usagi breaks and I'm dead weight again. She crushed every single one of those thoughts like bugs, one after another, because entertaining any of them for longer than a second was how you actually made them come true.

At the next bend, Semireiya slowed. Not by much. Enough that Rikka clocked it anyway, because clocking Semireiya's tells had become an involuntary hobby somewhere around the burned node. Semireiya's hand pressed harder into the rail, her breathing stayed steady, but her eyes did that thing, that half-second lag where her focus seemed to be dragged into place instead of just landing there, and something cold dropped straight through Rikka's ribs.

Usagi noticed too, closed the gap, pressed two fingers to Semireiya's wrist, the motion practiced, automatic, and Semireiya, for once, didn't pull away.

Usagi murmured something in Japanese, low and urgent.

「大丈夫…今ここ…」It's okay... right here, now...

Semireiya blinked, slow, once, and nodded.

Rikka didn't love any of this. Didn't love watching the person who'd hauled her out of that condemned block start glitching like a machine on its last cycle. But she loved it even less on the days Semireiya tried to sell everyone the invincible act, because at least this, whatever this was, was honest.

They found a narrow access pocket that opened into an alcove, and bolted to the wall inside was something that, at a glance, was garbage. A tangle of wires wrapped around a chunk of scrap metal, taped to a bracket under layers of old adhesive and peeling labels, with a tiny scavenged power pack and a coil that gave a faint pulse whenever the air pressure shifted.

Usagi's antennae tipped toward it, eyes going wide. "Scrambler."

"That thing?" Rikka said. "That's not a scrambler, that's a crime scene."

"It is real," Usagi said, shaking her head fast. "Someone built it from junk, but it works. It makes... chasing hard."

Semireiya's gaze locked onto it and didn't move, her whole posture gone rigid, and Rikka got there half a second later: same thought, same math. MITA's tag. If they didn't do something about it, the city was going to keep closing in no matter how many clever little detours they pulled.

Rikka crossed her arms. "No. That thing is bait."

"Or it's help," Usagi said, and the please was right there in her face even though she didn't say it.

"Help doesn't exist down here," Rikka said. "Only trades."

"We don't have time for purity," Semireiya said, low and even. "We have time for one controlled attempt."

Rikka opened her mouth to argue the point into the ground, the way she argued everything, and then she remembered Semireiya nearly sliding into that ENVY surge back at the last stop, and Usagi's tears, and MITA's stupid delighted laugh, and she swallowed the whole argument whole. "Fine," she said. "But short. If it sparks, we move."

Semireiya stepped up to the scrambler and studied it without touching, clearly not trusting it any more than Rikka did, just trusting the math instead, a small chance beating no chance every time. Usagi stood at her side, hands clasped together tight enough to be holding herself upright. Rikka took the corridor, eyes on the dark behind them, because someone had to actually watch the door while the other two gambled.

Semireiya flipped the taped switch. The totem pulsed once. Nothing changed that Rikka could actually see, but she felt it anyway, a faint pressure wave running under everything, a jitter she couldn't name sitting at the back of her skull like static trying to become a headache.

"It's working," Usagi said, antennae trembling.

Rikka didn't relax. "How long?"

"Seconds," Usagi said. "Not minutes."

Semireiya said nothing. Her eyes went slightly unfocused, like she was looking straight through the wall into whatever was underneath it, and Rikka's skin crawled.

Here we go.

Semireiya's breathing slowed, then stopped for a fraction of a second that felt much longer than a fraction of a second had any right to. Nothing around them shifted, not really, but Rikka watched it happen in Semireiya's posture anyway, a small stiffening, like her whole mind had just been yanked sideways into some layer where time ran on different rules.

Usagi grabbed her hand immediately. "Semireiya."

Semireiya didn't look at her. When she finally spoke, her voice had gone completely flat, like she was reading off something only she could see.

"Checksum... audit."

Rikka's mouth went dry. "What."

"/Root overlap," Usagi whispered.

Rikka hated that phrase specifically, and it wasn't because she doubted it was real, it was because every single time it showed up, it meant somebody's control had just become optional.

Semireiya's fingers twitched. The totem pulsed again, the jitter turning harsher, the device itself straining to keep up. She inhaled sharp, then her head jerked, like something invisible had just hit her.

Rikka stepped in without thinking. "Hey. Semi."

Semireiya's eyes snapped back into focus, but the focus looked like it hurt. "Resistance. It's... dragging."

"Stop," Usagi said, voice shaking. "Stop now."

"If I stop now, it locks again," Semireiya said, jaw clenched.

Rikka didn't fully understand what locks meant in this context, but she understood the shape of the problem perfectly: Semireiya was about to push way past sane, because pushing past sane was the only tool in her entire kit.

Semireiya's hand locked onto the rail. Her other hand hovered near her own chest, like she was trying to physically drag something out of herself. Usagi wrapped both hands around Semireiya's wrist, grounding, firm, tears already coming back, furious and helpless at once.

「やめて…お願い…」Stop... please...

Semireiya's breathing went shallow. "Trace... eraser. Partial."

Rikka's throat tightened. Partial meant it wasn't clean. Partial meant they were about to pay full price and keep the problem anyway.

The totem pulsed one more time, the coil gave a sharp crackle, and the jitter softened, like the device had done its job and was already dying from the effort.

Usagi flinched. "It's ending."

Semireiya's shoulders tensed, the pressure behind her eye surging, visible in the way she blinked too slowly, too hard. Rikka recognized the shape of it immediately: not a fight against MITA this time, a fight against herself, same sharp dangerous edge, just turned inward.

"I can finish it," Semireiya said, voice dropping, rough.

Usagi shook her head, fast. "No."

Rikka stepped in and grabbed her collar, light, just enough to force eye contact. "Semireiya." Sharp. Real. "You don't get to win like that."

Semireiya's eyes narrowed, irritation flaring. "Move."

Rikka didn't move. She said the line she'd been sitting on since the catwalk.

「セミレイヤ、今は"勝つ"じゃない。"帰る"だ。」Semireiya, not "win." "Get home."

Semireiya froze. It wasn't the words doing it, words never worked on Semireiya, it was that they happened to be true, and true was the one thing she'd never once figured out how to argue with. For a moment her jaw trembled, some last argument dying behind her teeth. Then she exhaled hard, forcing whatever it was back behind a door she'd apparently only just discovered existed.

Her shoulders dropped, just a fraction. She swayed. Usagi caught her instantly, pressing in close, holding her up with a strength that had no business fitting inside someone that size. Semireiya's hand shot out to the wall to steady herself, fingers dragging fresh lines through the grime.

Rikka let go of the collar and looked at Usagi. "Status."

"She's here," Usagi said, voice thin but holding. "But it hurts."

"Trace reduced," Semireiya said, eyes open but unfocused at the edges. "Slight. Not enough."

Rikka let out a laugh that came out more like pain than a laugh. "So we suffered for slight. Great."

Semireiya didn't answer that one.

"The proof," Usagi said, glancing at her pouch and back up, "for Kei."

"We keep it," Rikka said, jaw tight. "We don't lead trouble to him."

"Agreed," Semireiya said, and her gaze sharpened on the word in a way Rikka didn't miss, clipped, over-strict, like the second she let herself relax even a little she might slide right back down.

The dead-zone hadn't lifted. Still no comms, still no backup, still nothing but the three of them and whatever was left of a plan. Rikka shoved herself back into route mode. "We move. Now. Before the Hymn finds this pocket."

They left the totem where it was. Rikka gave the wall next to it one short satisfying kick on her way past anyway, because some things you did for closure, not tactics.

They climbed up through a cramped access ladder and out into a narrow corridor that opened onto an abandoned entertainment strip: dead signage, shutters welded down by rust, a whole row of little booths built into the wall like private boxes for people who wanted to sing, or cry, or just disappear somewhere nobody could see them do it.

Rikka recognized the layout immediately, and something behind her ribs pulled tight in a way she didn't love. "Don't get excited," she muttered. "These are not safe."

Bunny looked at the booths like they were some kind of miracle anyway. "Sound... damp."

"Seconds," Semireiya said, the muscle in her jaw standing out. "Not longer."

Rikka checked the nearest booth. The door sat slightly open, a thin line of light leaking out, not enough light to feel like good news. She pressed her ear against it. Silence, no voices, no movement, but underneath the silence she could hear the infrastructure humming, the specific hum of a power feed that had been used recently.

Someone had been here.

She eased the door open and slipped inside first. The booth was tiny: a bench, a cracked screen, old mic cables coiled up like dead snakes nobody had bothered burying. The air smelled of dust and somebody's abandoned perfume.

On the screen, a map overlay flickered, faint but readable, not a full system map, just a partial schematic: under-city channels, drain forks, and one highlighted path that clearly dodged the recent sweep cadence lanes. Rikka's heart kicked hard.

"Usagi," she said. "Look."

Usagi squeezed in, still bracing Semireiya with one arm, and leaned toward the screen. Semireiya came in last and pulled the door almost shut behind them, leaving just enough of a gap to keep the sound from carrying without actually sealing anyone inside a box.

"This is..." Usagi's eyes went wide. "A route."

"Yeah," Rikka said, jabbing a finger at the overlay. "And it's curated."

Two marks on the map didn't belong with the rest of the schematic. One was a clean line drawn straight over a drain fork with a tiny notch beside it, more like a deliberate instruction than graffiti some bored NPC had left behind. The other mark traced a route that looked way too easy, straight and inviting and lined up perfectly with a corridor running newer infrastructure than anything around it.

Her skin crawled looking at it. "That one's bait," she said. "It's too nice."

"The other one," Usagi said, nodding fast, "the notch mark, it's like..." and stopped herself before finishing.

Semireiya's gaze stayed locked on the notch mark. Her face didn't shift, but Rikka caught it anyway, recognition sitting there with absolutely no relief attached to it.

"Someone," Rikka said, quiet, "is helping."

"IRIS...?" Usagi said, and swallowed the rest of it.

Semireiya didn't confirm it. Didn't deny it either. "We use the marked route," she said. "We do not trust anything that looks convenient."

Rikka nodded, not because she loved owing anyone anything, but because she wasn't stupid enough to turn down a lifeline when the whole floor was actively on fire.

Usagi pulled the proof strip out of her pouch just long enough to remind herself it still existed, then tucked it away again.

"Kei needs this," she said. "But we can't go to him yet."

Rikka glanced at the booth door. Through the sliver gap, a faint rhythm crept in from outside. The Hymn. Not right on top of them. Closer than she liked.

This booth was a pocket, not a bunker, and their entire run of luck had rolled a natural seconds instead of a full rest.

Rikka turned back to the screen and burned the overlay into memory as fast as she could: three turns, a ladder drop, a low conduit run, then a service door that skipped the main sweep lane entirely.

Semireiya leaned in and traced the notch-mark path with one finger. Her hand trembled, just slightly, and she pressed harder against the screen like that would hide it. It didn't. Usagi noticed anyway and tightened her grip on Semireiya's arm.

"Semireiya," she said, low. "Breathe."

Semireiya did. One breath. Two.

Something twisted in Rikka's chest, not fear this time, an uglier kind of gratitude. She'd been the one who got rescued, and now she was standing here watching the person who did the rescuing pay the bill for it. Rikka hated that particular math, hated that the city always seemed to send the invoice to the wrong person.

Somewhere outside the booth, a soft metallic click sounded. Not the booth door. A corridor shutter, close by.

Semireiya straightened instantly. "Time."

Usagi's antennae angled toward the gap. "It's moving past. Not far, though."

Rikka nodded and pushed the door fully open, checked the corridor, empty for now, low-light cover and nothing more than that. "Move," she said. "And if anyone asks, we were never here."

Usagi threw the booth one grateful look on her way out, then followed, still holding Semireiya's arm. Semireiya went last, and as she stepped through, her gaze flicked once to the booth screen, to the notch mark, to the bait route. For a second Rikka thought she saw actual anger there, not at the map itself, at the idea that somebody out there got to move them around like game pieces. Then Semireiya's face went neutral again, like a screen going back to standby.

They took the notch-mark path. The dead-zone slowly started to thin, and Rikka felt the ambient signal creep back in like the whole world letting out a breath it had been holding, not enough for a clean call yet, but enough that the city's background static started existing again.

Rikka didn't celebrate any of it. More signal just meant more eyes.

They reached the first ladder drop and got moving. Rikka went down first again, on principle, because if the ladder was going to give out on somebody it was going to be her and not Usagi. Her boots hit the grating, and she looked up. Semireiya was coming down, controlled, slower than usual. Usagi hovered right behind her, ready to catch if it came to that.

Something in Rikka set its teeth. "We're ending this quest segment here," she muttered, mostly to herself. "You don't get to fall apart until after we survive, those are the rules."

Usagi heard it anyway and gave a small shaky nod, genuinely agreeing to the terms. Semireiya didn't comment. She just kept moving.

They slid into a low conduit run where the air ran warmer and the pipes swallowed the sound of their steps. The Hymn cadence drifted off to the left, hunting a different line entirely. Whatever that partial scrub had actually done, it had done something, even if it wasn't pretty.

It wasn't safe, not even close, just marginally less immediate than it had been ten minutes ago, and in this city, apparently, that counted as a conclusion.

Rikka held the route in her head and made her voice come out steady. She felt something crystallize before she even opened her mouth, something that sounded suspiciously like an actual rule. Fine. Let's actually try sticking to one for once, Rikka.

"No more fixed nodes," she said. "No more this is my place. We rotate, we keep moving, we stay hard to predict."

"Okay," Usagi said.

"Agreed," Semireiya said, eyes forward.

Rikka didn't smile. She didn't have the energy left for it. But moving into the next bend, away from the burned node, away from MITA's laugh still rattling around somewhere in the back of her skull, away from a booth that had only ever bought them a few seconds of air, something settled into place inside her anyway.

Not comfort.

Not peace.

A new rule.

If the city wanted to keep erasing their homes, fine, then they'd simply stop handing it homes to erase. And somewhere further ahead, price-tag Kei was waiting with his plan and his "payment," with absolutely no idea that his own timeline had already been forced open early.

Rikka jammed her shaking hands into her pockets and kept walking anyway.

Surviving was one problem.

Whatever came next was going to be worse.