After their car falls through an ice road, an Indigenous couple makes their way to an isolated cottage. Suffering from hypothermia, they are saved when the cottage owners, a non-Indigenous couple (one of whom is a nurse) arrive. After the injured couple have been treated, the cottage owners discover that the "accident" was not necessarily accidental. As the characters uncover layers of history and alternate agendas, On Thin Ice's cracks radiate towards a shocking and brutal ending.