Set in 1944, 5 years after the Civil War which tore Spain apart, Ofelia, a young girl played by Ivana Baquero and her pregnant and unwell mother played by Ariadna Gil, travel to an old mill in the countryside, where her mother’s new husband, played by Sergio Lopez, is based. He is a sadistic army officer who has been sent to deal with a guerrilla uprising. Ofelia is a lonely girl with a love of books and fairy tales. Once the new baby arrives, Ofelia is increasingly alone and friendless.

During the night, Ofelia meets a fairy and together they go to an overgrown maze where they meet the faun Pan who tells her that she is a princess from a kingdom in the underground. He also tells her she must complete three dangerous task in order to claim immortality and be reunited with her father. In this increasingly dark, harsh and violent world, Ofelia lives in her magical world trying to survive her tasks and see her father and king again.