After participating in a séance, young Laura begins to behave strangely. Alarmed, her parents ask Father Olmedo, one of the few exorcists authorized by the Vatican to intervene in cases of demonic possession, for help.

In an inaccessible place between the mountains and isolated from the world, a school is located next to an old monastery. The students are rebellious and problematic young people who live under the strict and severe discipline imposed by the center to reintegrate them into society. The surrounding forest is home to ancient legends, threats that are still valid and that will immerse them in terrifying adventures.

Recounts the experiences of a middle-class family, the Alcántaras, during the last years of the rule of Francisco Franco and the beginning of the Spanish Transition to democracy.