Alma and Alex, two adolescent sisters, are survivors of a catastrophic event. They live deep in the woods with their Mother, a strict, over-protective woman who has sheltered them from ominous presences, the Shadows, which live in the daylight and infest the world beyond the river, a border for Alma and Alex. When they follow Mother, out for hunting, Alma and Alex start a series of events which will make them discover the truth about the Shadows and their own reality.