Fiona and Gus's marriage has veered off course. Fiona's mental health is shaky at best, and is now further strained under the weight of a transgression that she would like to both forget and repeat. Gus, a pro snowboarder turned backcountry guide, is exhausted by Fiona's mood swings and her ambivalence about their relationship, but mostly by the impact of her erratic behaviour on their eight-year-old daughter, Ruby. Ruby loves them both, but has a much closer relationship with her father, and has stopped talking in the face of the tensions between her parents. In the midst of this marital crisis, Gus takes Ruby's class on an overnight trip into the wilderness, where Ruby is one of only two children to survive the avalanche that kills the others, including her beloved father. While Fiona's mental health is unravelled further by grief, Ruby is flattened by Gus's loss. After the search ends with no sign of her father, Ruby is determined to find him herself, using the survival skills he taught her and believing that he must still be alive. Her trek back into the snow sets off events that stretches her own resourcefulness and her mother's fragile coping skills to the breaking point.