In the remote, windswept landscapes of Iceland, elderly couple Björn and Áslaug live a serene life in their secluded cabin. Their tranquil existence is violently interrupted when Jack, an American hiker and ex-Marine, arrives with a shocking claim: he believes Björn is his estranged father from a past affair in the United States. As Jacks's mental instability surfaces, the couple finds themselves prisoners in their own home. Björn and Áslaug must navigate James's erratic behavior while confronting painful secrets from their past. Jacks's demand for a DNA test and his increasingly violent behavior push Björn to concoct desperate lies, while Áslaug hides her own involvement in the dark history that connects them all. When Áslaug attempts to escape, Jack's response is brutal, leading to a deadly encounter with an innocent Icelandic hiker who stumbles upon the scene. This act of violence marks a point of no return for Jack, further endangering the couple. As Jack forces Björn into a twisted bonding experience, details of Jacks's troubled childhood and his longing for a father figure are painfully revealed. In a climactic campfire confrontation, past sins and buried betrayals come to light. Björn must summon a strength he never knew he had to protect his wife and confront Jacks's unraveling mind. The flames of the campfire reflect the intensity of their struggle, leading to a shocking revelation about Jacks's true parentage and a desperate fight for survival.