Briardark

Dr. Siena Dupont leads a team of ambitious researchers on the Alpenglow glacier expedition, an assignment that should make their careers. Thirty miles into the Deadswitch Wilderness, the group comes upon a missing hiker hanging from a tree. Then the satellite phone goes dead, and the corpse vanishes without a trace.

The wilderness then stops obeying the rules. Siena's map no longer matches the trail, and the glacier the team came to study has melted away. A tunnel through the hollow of a tree draws her toward a hidden cabin, where a stranger waits with a sinister message.

A second thread follows Holden Sharpe, an underachieving IT worker. He comes across a decommissioned hard drive holding an audio file: Siena's own recording of an expedition falling into chaos and death. Holden becomes obsessed with it and sets out to learn what happened, heading toward the edge of Deadswitch and the impossible things inside it.

Briardark is cosmic survival horror with a twisty plot, told through two linked storylines, one in the wilderness and one in pursuit of its recording. It is the first book in a series and ends on a cliffhanger, so expect questions left open.