In Spain in 1944, Ofelia, an eleven-year-old girl with an overflowing imagination, moves with her mother, Carmen, to a mill in the midst of a forest, where they live under the command of the ruthless Captain Vidal, a Francoist officer obsessed with eliminating any resistance. Ofelia's life is a true chaos between the cruelty of the military regime and her attempt to adapt to a new home, but everything changes when she discovers a secret labyrinth near her house. There, she meets an enigmatic faun who reveals to her that she is the reincarnation of a lost princess. To return to her underground kingdom, Ofelia must complete three dangerous tasks that will test her courage and her nature.
As Ofelia delves into a world filled with fantasy and danger, her mother struggles with pregnancy and illness, while Captain Vidal threatens to dismantle any sign of opposition. As the violence and cruelty of the real world intensify, Ofelia faces monsters of her imagination and the harsh realities surrounding her. Caught between fantasy and the brutality of the adult world, the young girl must choose between meeting the faun's demands or attempting to protect her mother. The story intertwines the struggle for survival with the search for hope, showing how innocence can be a refuge in dark times.