On the newly colonised planet Silverion, three teens follow a rhythmic signal into a forbidden cave and uncover something that should not be there.
Zorion sat with Lea and Miko on the lip of a crater that glowed faintly in the planet's silver dust. Below them, Silverion stretched under a cold star, all sharp ridges, pale rocks, and shadows that looked deeper than they should. Since their families had landed here, every day had delivered a new wonder, or a new warning.
Zorion was fifteen and liked warnings least of all. He liked doors that were shut, signals nobody understood, and places the adults marked as off-limits. Lea liked answers. If she couldn't find one, she built one. Miko liked neither danger nor rules, but he followed them badly, which was almost the same thing.
That night, the colony's comm tower had caught a signal pulsing up from beyond the settlement perimeter. Not speech. Not static. A pattern, steady as a heartbeat. The adults had argued over it for hours, then locked the data behind their own encrypted systems. Lea had copied it anyway, slipping it onto her holowatch while everyone else was distracted.
Now the three of them stood at the mouth of the cave she had traced from the signal map. The ground under their boots shimmered with a mineral dust that caught the dark and gave it back in silver sparks. The cave itself was a jagged cut in the rock, breathing cold air that smelled faintly of metal and rain, though there had been no rain on Silverion since they arrived.
"Tell me again why we're here," Miko whispered.
"Because something out here is talking," Zorion said. He kept his voice low, but not low enough to hide the strain in it. "And the adults don't know how to listen."
Lea checked the holowatch. The signal on the display was clear now, pulsing faster, as if it knew they were close.
They stepped inside.
The walls shone with thin lines of light, like veins under skin, and the sound of their breathing came back to them wrong, stretched and delayed. Zorion touched the rock beside him. It was warm.
Then Lea stopped so abruptly that Miko nearly bumped into her. The holowatch flashed once, hard and white.
"Zorion," she said, her voice suddenly thin. "Look at this."
The cave floor split with a sharp crack, and something below it answered with a deep, rising pulse. Stone slid apart to reveal a spiral stairway dropping into the dark, each step lit by the same pale glow as the signal.
From below, something moved.