The story follows Ofelia, a young girl traveling with her pregnant mother to live with her new stepfather, Captain Vidal. Vidal is a sadistic officer tasked with rooting out anti-fascist rebels in the mountains. To escape the brutality of her daily life, Ofelia discovers a mysterious stone labyrinth where she meets a Faun. The creature claims she is a lost princess and must complete three dangerous tasks to reclaim her throne.