1850. Wolves plague the forests. More and more people are disappearing. The mutilated cadavers present precise surgical cuts along with salvage gashes. It’s a contradiction that terrorizes the local villagers, who are too frightened to enter the forests. The legend of the “Werewolf of Allariz” expands throughout the land. Barbara and her sister Josephine live in an isolated house in the forest. They only feel safe when a traveling vendor by the name of Manuel, Josephine’s lover, and who, Barbara secretly admires comes to visit.

Manuel accompanies Josephine to the city. When he returns, Barbara and Manuel become entangled in a passionate romance. But Barbara suspects that her sister never made it to the city. Why is Manuel the only person in the valley not afraid to enter the forest? What secrets are hidden under the cloth roof of his wagon? Her suspicions are confirmed: Manuel is the werewolf feared by all. Her happiness converts into absolute horror. Her love, into hate. She is overcome with feelings of vengeance. Barbara will do anything in her power to destroy Manuel Romasanta.

Manuel is captured. He proclaims his innocence based on a curse that turns him into a werewolf. The local society becomes divided. While the local villagers fear he may be released, the upper class citizens, led by the renowned anthropologist Professor Phillips justify his acts due to an illness called licantropy. But in reality, who is Manuel Romasanta? A cold-blooded killer? A werewolf? A man who suffers from licantropy? Manuel is the only one who knows the truth.

The film is based on the true-life story of Manuel Blanco Romasanta, the traveling vendor, who confessed to the murders of thirteen people, using their body fat to make soap. Romasanta was tried in Allaríz in 1852 and avoided capital punishment by proclaiming he was a werewolf. Barbara was the lone survivor of four sisters.