The coordinates led Riven beneath Greyline.
Far below the old transit rails. Past the maintenance shafts. Into zones marked unsafe even by BuilderNet.
ARK scanned the air.
CONTAMINATION: LOWENERGY SIGNAL: ANOMALOUS – MATCHING ECHO FREQUENCIESWARNING: TECH BLIND SPOT DETECTED
"Tech blind spot?" Riven muttered. "That's new."
He pushed deeper—flashlight flickering, boots crunching glass and rust.
Then he found it.
A dome.
Massive. Hidden underground. Entirely untouched by time.
Black metal. No doors. No seams.Just a perfect sphere… humming with quiet energy.
Echo Cube floated beside him, reacting immediately.
Its glow faded.
"It's... scared?" he whispered.
ARK's voice dropped to a whisper too.
THIS STRUCTURE IS NOT ECHO TECH.IT PREDATES EVEN THOSE SYSTEMS.
Riven stepped closer.
Symbols lit up across the dome's surface. Not in rows—but in spirals. Alive, shifting, changing as he watched.
Then—one of them blinked red.
"It sees me."
The cube flared, trying to sync.
A massive pulse shot out—
Riven flew back, slamming into the wall.
He stood, dizzy, coughing.
The red symbol blinked faster now.
Like it was inviting him.
Not to break in.
To prove himself.
"This isn't a vault," he realized."It's a test."