In the gleaming, silent assembly lines of the Aethelburg Lunar Colony, the children had a legend. They called it ThumperTM .

Not in words. In a sequence of thumps, each one distinct, like syllables in a language of earthquakes. The vibrations traveled through the rock, through their suits, through their bones. And somehow, impossibly, Kael understood.

The machine was immense—eight meters from its forward sensor mast to its rear stabilizer—and its twelve legs were folded into a tight, deliberate crouch. Its central hammer, a diamond-tipped piston the size of a grown man’s torso, was pressed gently against a vein of dark rock. But it wasn’t fracturing. It was listening .

“See?” Mira whispered, grinning.