Alucarda (Spanish title: Alucarda, la hija de las tinieblas, or Alucarda, the daughter of darkness) is a 1978 Mexican horror film directed by Juan López Moctezuma, and starring Tina Romero in the title role. Often thought to be based on the 1872 novella Carmilla, it revolves around two teenage orphan girls living in a Catholic convent, who unleash a demonic force and become possessed by Satan. Though it is a Mexican Spanish language film, it was originally filmed in English, as evidenced by the fact that the lip movements match the dubbed English dialogue. It was released in theaters across Mexico on January 26, 1978.
The film takes place in a Mexican convent that houses nuns and is also an orphanage. Alucarda, a fifteen-year-old orphaned girl, has lived at the convent her entire life. Justine, another orphan girl of similar age, arrives at the convent. She and Alucarda become very close friends and form a relationship that borders on being sexual.
While playing in the nearby forest, the girls stumble upon a band of mysterious gypsies and subsequently unleash a demonic force after opening a casket at a nearby burial site. A bloody chain of events follows after both Alucarda and Justine become possessed by the Satanic entity and wreak havoc on the convent and its inhabitants.