Aydin followed the click. It came through the wall ahead like something made. Violet warmed on his wrist.

  CHRONO ESTIMATE: 71 HOURS SINCE SUBTERRANEAN ENTRY

  REWRITE WINDOW: 9 MIN

  PATH STABILITY: LOW

  Aydin stopped so hard his shoulder thumped stone.

  “Seventy-one what.”

  HOURS.

  He stared at the bracelet. “That is not possible.”

  QUERY: WOULD THAT INFORMATION HAVE IMPROVED SURVIVAL OUTCOME

  Aydin opened his mouth. Closed it. Opened it again.

  “I hate how often you say things that sound stupid and correct at the same time.”

  He kept his palm on the wall anyway. The bend opened and the cave gave up the lie. Not cave anymore. City. Dressed masonry, fitted blocks, seams too straight to be natural, old plaster clinging to one corner.

  “I fell into a city.”

  OBSERVATION: YOU FELL

  CORRECTION: YOU CONTINUE FALLING

  Aydin let out one short laugh.

  “Up?”

  UP VECTOR: INCONSISTENT

  “That’s illegal.”

  NEGATIVE. IT IS COMMON

  He moved anyway. Cobblestones ran beneath his boots for a stretch, then kept going up the wall like gravity had started an argument and walked away before finishing it. Crystal dust lay in old grooves where carriage wheels might once have rolled. Ahead, an archway had fused half shut in frozen runoff crystal.

  Aydin crouched. He pressed two fingers down. Tugged. The sand at his cuffs stirred, enough. A thin reluctant line dragged itself along the grout.

  “Okay,” he muttered. “Better than nothing.”

  He asked for less, just movement. The thread improved immediately, nosing into a seam and sliding forward.

  HOST ADAPTATION DETECTED

  MOTOR STRAIN: LOWER

  RECOMMENDATION: CONTINUE WITH SMALL FORMS

  Aydin blinked. He pinched a pebble from the cracks and tucked it into a notch in the wall.

  MARKER DECAY: 6 MIN (EST.)

  “That’s not a marker.”

  CORRECTION: IT IS A WARNING

  Then he heard it. A pressure hiss. A metallic tick. His sand-thread stopped in the crack ahead.

  Aydin swallowed. “Okay.”

  The corridor narrowed. Pipes ran along the walls. A grate had melted into the floor. Glass-sand glittered across the metal.

  Violet chimed.

  ACOUSTIC TRIPWIRE: ACTIVE

  PREDICTION CONFIDENCE: 23%

  DO NOT STEP ON THE METAL STRIP

  Aydin looked down at the exact strip he had been about to step on.

  “You could have opened with this level of usefulness.”

  No response. He slid his sand-thread ahead instead. Where it flowed smooth, he trusted the stone. Where it snagged, he stepped elsewhere.

  The first monster announced itself with a soft chime, low-slung and hinge-limbed. Its split throat cavity was lined with trembling crystal nodules.

  Aydin froze. His boot shifted half an inch anyway. A rivet pinged. The nodules flared.

  RING EVENT: 1/3

  PREDICTION: SECOND CONTACT WILL TRIGGER RESPONSE

  Aydin lifted both hands.

  “Okay, okay.”

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  He pulled sand around his boot instead, padding the sole in a thin muffling wrap and easing his weight sideways. The creature’s throat vibrated harder.

  RING EVENT: 2/3

  ALTERNATIVE: OBSTRUCT THROAT VIBRATION

  Aydin bared his teeth.

  “And how exactly do you think I should do that.”

  PACK SAND INTO NODULE CAVITY

  TARGET: LOWER SPLIT

  “Great. Love instructions that arrive while I’m dying.”

  A tight spiral of sand shot off his wrist and punched into the split throat. It packed between the nodules and ruined the resonance. The thing jerked. Aydin lunged and slammed its head into plaster. Crystal cracked. The sound came out wrong. The creature spasmed and went down.

  For two seconds the corridor held its breath. Then, from somewhere deeper, something answered. Not loud. Worse than loud. A tiny distant crystal tap.

  ACOUSTIC RESPONSE: DETECTED

  RECOMMENDATION: MOVE

  “I was already doing that.”

  He ran, quietly, which was a lot harder than he felt the world appreciated. He took the turn with his pebble marker.

  The pebble was gone. The doorway behind him had sealed itself in frozen runoff.

  Aydin stopped. “You changed the map.”

  AFFIRMATIVE

  “Do you have a stop button.”

  NEGATIVE

  “Wonderful.”

  He turned the other way. The next street opened too wide. Then the world tipped. What had been ground kept going up the wall. A broken fountain hung sideways in the air, its spill frozen into a crest of pale crystal. Lampposts rose in a vertical line along what had once been the square’s edge.

  Violet flared.

  REWRITE WINDOW: 6 MIN

  SIGHTLINES: HIGH

  CROSSING WINDOW: 7 SECONDS

  RECOMMENDATION: DO NOT STOP IN THE CENTER

  Aydin realized he had already stopped.

  OBSERVATION: YOU ARE STILL IN THE CENTER

  A thin yellow edge slid over his shadow.

  Aydin’s stomach dropped. “Oh.”

  The Mirrors arrived without sound, glass-mandibled and herding.

  Aydin bolted for the nearest broken structure, a collapsed plinth jutting from the tilted cobbles. The yellow tag snapped after him.

  Violet chimed fast.

  SIGHTLINE CLUSTER: THREE

  LEFT COVER FAILURE PROBABILITY: 82%

  RIGHT COVER VIABLE

  DO NOT RUN STRAIGHT

  “That was actually useful.”

  CORRECTION: IT WAS HELPFUL

  He hit the plinth and dropped behind it. Across the square he spotted the sideways service stair. Then the market-stall frame bolted into the wall, its coin-chain dangling.

  Aydin flicked a pebble. The chain clinked. Two Mirrors twitched. Then looked straight back at him.

  Aydin swore.

  RESULT: DISTRACTION INSUFFICIENT

  CAUSE: TARGETS MAINTAIN VISUAL PRIORITY

  SIMULATION: PEBBLE DISTRACTION FAILURE, 68%

  RECOMMENDATION: USE SAND

  “Great. Thank you. Very helpful after the failure.”

  PROJECT SAND ACROSS STALL FRAME

  AMPLIFY CONTACT

  CREATE MULTI-POINT SOUND

  DENY SIGHTLINE

  Aydin moved his hands. Sand came up in three thin lines. One rattled the stall frame. One smeared across the cobbles. One burst across a Mirror’s face ridge. The chain clattered.

  The Mirrors reacted.

  THREE SIGHTLINES LEFT

  RIGHT COVER VIABLE

  MOVE NOW

  Aydin moved. He cut left first, then snapped back right while the chain rattled behind him. Another Mirror lunged at the false motion smear. Aydin slid into the next cover.

  The yellow outline on his shadow flickered. Cover did more than hide him here. The moment he got behind it, the tag on his shadow flickered.

  “Okay, that’s a real rule.”

  SIGHTLINES: HIGH

  CROSSING WINDOW: 4 SECONDS

  He ran. A Mirror launched. Aydin threw sand in a thin curtain across its face ridge. He hit the sideways stair. His boots slipped. Sand jammed under his palms and soles. He hauled himself to the ceiling-door seam and slammed his shoulder into it.

  Nothing.

  REWRITE WINDOW: 2 MIN

  CROSSING WINDOW: 2 SECONDS

  RECOMMENDATION: COMMIT

  Aydin slapped his bleeding forearm against the seam. The seam clicked.

  “Oh, you are kidding me.”

  The Mirrors hit the stair below him. Aydin shoved again. The latch gave. He threw himself through and slammed the door behind him as claws scraped the far side.

  Then he lay there laughing once, helplessly. Violet said nothing. She did not need to.

  Later, he stopped trying to understand the city all at once. Aydin learned to survive it in fragments: a sand-thread creeping around corners, a shallow veil to blind a sightline for one second, a stair of compacted sand that collapsed the first time.

  “I hate this place.”

  MOTOR RESPONSE IMPROVING

  SAND SHAPE STABILITY: +12%

  “I’m glad one of us is having fun.”

  CORRECTION: I DO NOT EXPERIENCE FUN

  “Shocking.”

  A Duster taught him the real rule. Rot grit did not stop sand. It punished sloppy shaping. Big forms sagged. Broad pulls broke apart like wet bread. So he stopped being broad. He threaded sand into joints instead of throwing it in sheets.

  When he got it right, Violet started changing too. Early on she warned. Later she predicted.

  LEFT FOOT SAFE

  RIGHT FOOT FAILURE PROBABILITY: 63%

  Then:

  TARGET WILL TAKE LEFT SIGHTLINE

  RECOMMENDATION: DENY VISION / MOVE RIGHT

  The first time that prediction saved him, a crystal jaw swept through the space his head would have occupied.

  “You keep getting less useless.”

  CORRECTION: I AM GETTING BETTER AT YOU

  “That is somehow worse.”

  Eventually he met patrols, three Jawglass moving in coordinated lanes. He liked things better when they were stupid. A sand-thread caught one ankle. A veil blinded the second. A wedge jammed the doorframe. The first Jawglass hit the second. The third lost its footing on a sand-scuffed patch. Aydin slammed its head into masonry and pinned its jaw with grit.

  Then stood there breathing hard.

  HOST CONFIDENCE: IMPROVING

  “Do not start complimenting me now.”

  QUERY: DEFINE “COMPLIMENTING”

  “No.”

  A maintenance district opened ahead. Seams. Hatches. Pressure lines.

  CHRONO ESTIMATE: 74 HOURS SUBTERRANEAN

  EXIT VECTOR: PROBABLE

  SIMULATION CONFIDENCE: 81%

  “Seventy-four hours.”

  AFFIRMATIVE

  “That feels fake.”

  NEGATIVE

  One lane threat. One sound trap. A broken stair to the left. A narrow service seam to the right.

  DO NOT TAKE THE STAIR

  “See, now that feels personal.”

  PRESSURE GRADIENT: FALSE ASCENT

  RIGHT PATH SURVIVAL PROBABILITY: HIGHER

  He followed her call. A sound-trap creature unfolded from a niche. A Jawglass silhouette moved in the far lane. Aydin sent his sand-thread under the grate. Found the safe path. Blurred one sightline. Yanked a maintenance frame loose.

  THREE STEPS LEFT

  DO NOT STOP

  TARGET COMMITTING RIGHT

  DEPLOY SAND LOW

  NOW

  A low wedge burst under the Jawglass foot.

  Aydin hit the seam. Sand locked his grip for one second. He pulled.

  Nothing.

  TRUST ME

  Aydin barked out a laugh.

  “That is an insane thing to say after three days of you grading mushrooms.”

  TRUST ME

  He obeyed. Sand packed under the latch plate. Leveraged. Lifted. The seam clicked.

  Air touched his face. Different.

  Aydin dragged himself through and slammed the hatch shut. He sat there in the dark, chest heaving.

  Still alive.

  Violet warmed once.

  EXIT VECTOR: PROBABLE

  HOST STATUS: ACTIVE

  Aydin wiped his face.

  “Yeah,” he whispered. “I noticed.”

  Somewhere ahead, the air shifted. Someone or something was there.

  For once, he did not joke.

  He listened.