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.

The enigmatic Mia (Anna Åström) bursts into the lives of Charlie (George Blagden), who is coming to terms with his father's death in rural France, and his fiancée Ella (Ellie Turner) in London. As the summer unfolds, it becomes appar