Several friends travel to Sweden to study as anthropologists a summer festival that is held every ninety years in the remote hometown of one of them. What begins as a dream vacation in a place where the sun never sets, gradually turns into a dark nightmare as the mysterious inhabitants invite them to participate in their disturbing festive activities. A couple travels to Northern Europe to visit a rural hometown's fabled Swedish mid-summer festival. What begins as an idyllic retreat quickly devolves into an increasingly violent and bizarre competition at the hands of a pagan cult.