The nightmare tells how in 1880 in a village in mountainous Galicia a series of mysterious deaths devastate the region. All the victims are young women, and murdered under mysterious circumstances. And the townspeople begin to suspect that the person responsible is Naim, a strange neighbor who lives apart, never leaving during the day. But Lúa, a young woman from the village who sees through her prejudices, will do everything possible to protect her most hidden secrets.