This film is excellent. I saw it a few weeks ago and should have posted about it then. Highly recommended.
The film is set in post-Civil War northern Spain, in 1944. A young girl, Ofelia (Ivana Baquero), moves with her pregnant mother Carmen (Ariadna Gil), and her stepfather Captain Vidal (Sergi Lopez), into a new home in the countryside. Vidal and his small army have been sent to the remote area to rid it of a small Republican militia.
Ofelia, who often immerses herself in ancient stories and fairy tales, finds an immense and ancient labyrinth near her new home. There, she meets a faun (Doug Jones) who reveals that she is the long-lost daughter of the King of the Underworld, and that to regain entry to her kingdom she must carry out three tasks. The faun gives her a storybook, which will tell her the details of the tasks.