The entrance to the buried chamber was a fissure in the permafrost that had opened recently—within the last few days, judging by the fresh cracks in the ice—and the darkness beyond it was breathing.
Marcus stood at the edge of the fissure, the wind whipping across the frozen tundra, and watched the steam rise from the depths. It pulsed. Inhale. Exhale. A rhythm that matched the signal they had been tracking for twelve hours. A rhythm that matched a heartbeat that had been beating in the dark beneath the Northern Wastes for millennia.
"Temperature inside the fissure is fifteen degrees warmer than the surface," Leo reported, his portable scanner flickering with data. "There's a geothermal source down there. Something that's been keeping the chamber stable for... a very long time."
"How lo
