The wealthy, powerful Snæberg clan has gathered for a family reunion at a futuristic hotel set amongst the dark lava flows of Iceland's remote Snæfellsnes peninsula. Petra Snæberg, a successful interior designer, is anxious about the event, and her troubled teenage daughter, Lea, whose social-media presence has attracted the wrong kind of followers. Ageing carpenter Tryggvi is an outsider, only tolerated because he's the boyfriend of Petra's aunt, but he's struggling to avoid alcohol because know what happens when he drinks. . . Humble hotel employee, Irma, is excited to meet this rich and famous family and observe them at close quarters. . . perhaps too close. . . As the weather deteriorates and the alcohol flows, one of the guests disappears, and it becomes clear that there is a prowler lurking in the dark. But is the real danger inside. . .within the family itself?