Below

The message had not come from the plateau.

Nadia had run the signal trace twice, which was thorough enough: the originating ping for the text was not from outside the station, not from across the ice, not from any satellite relay she could locate. It came from below.

She stood in the generator room with her back against the cold wall and did the math on what that meant. The station had no basement. The blueprints showed a single-level structure — five modules, crawlspace foundation poured directly onto permafrost. Permafrost that was, depending on which survey you trusted, forty to sixty meters thick before you hit rock.

She found the access panel behind the secondary fuel rack.

It had been moved recently — she could see the scrape marks on the floor, fresh through the dust. Behind it: a steel hatch, a ladder, and a descent into cold darkness that the blueprints did not contain.

She took the fire axe and her flashlight and went down.

The space below was not large — three meters of rough-dug room, insulated poorly, lit by a single battery lamp that had gone orange with age. The smell was stale air and cold and three people who had been down here for eleven days.

They were alive.

Eriksson was in the corner against the thermal blankets, eyes open, watching her come down the ladder. He was thinner, and he'd lost the careful professional calm she'd seen in his file photographs — what was left was something rawer, more tired. Mafi was asleep on her side. Paulsen was awake but unresponsive, staring at the ceiling with the fixed attention of someone working through a very long calculation.

"Dr. Chen," Eriksson said. His voice was steady. "I tried to warn you in time."

"You turned off your own emitter," she said. It wasn't a question.

"I installed it," he said. "And I was right to." He looked at the ceiling, then back at her. "When you came in this morning, I still thought there might be time. That if I told you not to switch off the generator, you wouldn't." His jaw tightened. "You disconnected it already."

"Four hours ago." She looked at him steadily. "Tell me what it does."

He told her.

The experiment they'd been running — officially a long-term acoustic survey of geothermal activity under the plateau — had involved broadcasting low-frequency pulses into the ice. Seismic mapping. Standard methodology. Eriksson had adapted the pulse array to a slightly unusual frequency after Paulsen's theoretical work suggested it would improve subsurface resolution.

The frequency was 18.98 Hz.

Two weeks into the survey, something had come toward the station.

"We don't know what it is," Eriksson said quietly. "We don't know if it's biological or geological or something with no category yet. We know it responds to the frequency. We called it toward us, and then it arrived." He looked at her. "The emitter was running on higher output as a deterrent — broadcasting back, overwhelming our original signal. It was working."

"Until I disconnected it," Nadia said.

"Until you disconnected it."

The space was very quiet. The battery lamp flickered.

Nadia thought about the walk-in temperature. The twenty minutes unprotected on the plateau. The unmarked snow around every exit.

"It hasn't gone through the walls," she said.

"No." Eriksson's voice was careful. "It's patient. Whatever it is, it has learned to wait."

Above them, very faintly, the heating system clicked.

Then, from somewhere along the outer hull, three sounds: distinct, deliberate, evenly spaced.

A pause.

Then three more.