Vivienne, a photographer from Manchester, arrives at a boarding house on a tiny Finnish island hoping to rekindle her creativity and heal her broken heart. Instead, she misses her wife. Her camera hangs at her side unused. And her fellow guests keep inviting her into the forest.

Vivienne quickly grows close with Ilya, the affable caretaker, and Gagarin, a rebellious mycologist. And when Gagarin confesses she's searching for a mythical bracket fungus—the Bigfoot of mushrooms—Vivienne throws herself headfirst into the cause.

The days pass in a blur of snow and birch trees and vodka. Yet the longer Vivienne spends in the forest, the more it consumes her. Haunted by lost time, inexplicable acts of violence, and rising tensions among the guests, Vivienne begins to suspect there's something darker behind Gagarin's determination. Because ambition always requires sacrifice. She's just not sure whose...