Spain. At late 60s years, Antonio Prieto is a successful writer who, suffering a creative crisis, decides to leave the big city and move to a remote town named Quintanar, in the deepest heart of Andalusia (South to Spain). Renting an old manor outside the town, Antonio meets beauty Berta, a real estate who introduces him in Quintanar, despite the apparent reject of the villagers. Trying to adapt himself to the nature and to the nights full of animal sounds, the rude character of the villagers and the insane atmosphere that rules the town starts to affect him, specially after to discover by chance that a man named Esteban lives imprisoned in an isolated cabin by the bartender and his wife due to his physical deformities and extreme brutality. However, Antonio finds in Padre Benito, priest of the town, a friend to talk about Quintanar, its history, and have a moment of peace. Meeting Berta's cousin Justa and her two daughters, older Sole and younger Rosita, the children accuse him to be Vimero. Puzzled about it, Antonio learns about a local legend, a mythical creature named Vimero, who is a shapeshifter that long time ago arrived to Quintanar from the mountains and killed some inhabitants. After them expelled him, Vimero cursed the town to be born with deformities for the later generations, causing fear in the town if the monster someday would return. Encouraged by Padre Benito, Antonio closes Berta as she feels attracted to him, but the tragedy happens: a night Sole is found dead and severely mutilated, plunging the town into pain and grieve, making that Inspector Mauri moves to Quintanar to find the killer. Convinced of Esteban's culpability, Antonio addresses Mauri about him, just to discover that Esteban escaped from the cabin and he is on the run. But this same night, when Antonio and Berta are in the old manor, the truth about the crime will reveal in the most bloody and horrific way.