Sarah (Kate Bosworth), Abby (Katie Aselton) and Louise (Lake Bell) are three good friends who have played together since childhood. In order to bridge the contradictions between the other two, Sarah specially organized a holiday trip away from the hustle and bustle of the city. They took a boat to an isolated island called Black Rock to embark on a treasure hunting adventure. There were laughter and quarrels along the way, and the inherent grudges in their hearts could not be cleared after all. During this period, they met Henry (Will Bouvier), a man they met that year, and Drake (Jay Paulson) and Alex (Anslem Richardson), who were hunting with him. As night fell, three pairs of men and women sat around the campfire and chatted happily. But as primitive animality replaced human nature, everything took a sharp turn for the worse, and killing suddenly came...