Alucarda (Spanish: Alucarda, la hija de las tinieblas, or Alucarda, the daughter of darkness) is a 1977 English-language Mexican supernatural horror film directed by Juan López Moctezuma, and starring Tina Romero, Claudio Brook, Susana Kamini, and David Silva. A loose adaptation of Carmilla (1872), it revolves around two teenage orphan girls living in a Catholic convent, who unleash a demonic force and become possessed.
Though a Mexican production, the film was shot in English. Internationally, it was released under several alternate titles, including Innocents from Hell and Sisters of Satan. The film has been noted by film scholars for its themes regarding national tradition versus modernity, as well as the tensions between science and religion, and the failures of both. Because of its depiction of nuns in emotionally-heightened, supernatural situations, the film has been associated with the nunsploitation genre.
In 1850, Lucy Westenra gives birth to a daughter, Alucarda, in a derelict colonial palace in the woods. Immediately after the child is born, Lucy begs a hunchbacked gypsy to bring Alucarda to a nearby stone-walled convent inhabited by an order of Catholic nuns, as she fears the devil will claim her daughter. As the gypsy flees with the infant, a demonic voice emanates throughout the palace as Lucy dies of complications from childbirth.
Fifteen years later, a teenaged Alucarda still resides at the convent. Alucarda swiftly takes an interest in Justine, a new orphan her age who has arrived, and is eager to become her friend. Alucarda quickly refers to Justine as her sister. While playing in a forest, Alucarda and Justine witness a band of gypsies holding a funeral procession. One of the men—the hunchback who helped deliver Alucarda—offers to sell Alucarda an amulet. Shortly after, the girls stumble upon the abandoned palace, and wander into a crypt. There, Alucarda professes her love for Justine, and the two make a pact that they shall die together. In the crypt, they unwittingly open the grave of Alucarda's mother, and are immediately overcome by a powerful supernatural force that reduces Alucarda to tears.
Later, during mass, Justine inexplicably faints. While Alucarda tends to Justine in her room, she goes into a fit and begins wildly reciting the names of demons. The hunchback gypsy appears in the room as Alucarda invokes Satan, and the girls, nude, perform a blood ritual. Meanwhile, while praying, Sister Angélica has a vision of Alucarda and Justine performing a Satanic ritual with the gypsies in the woods and engaging in a mass orgy. During the ritual, one of the priestesses is stricken down by Sister Angélica's invocation of God, and is killed.
The next day during school, Alucarda and Justine begin chanting and professing their dedication to Satan, much to the horror of the nuns and their peers. The nuns make several unsuccessful attempts to have the girls repent, one of which ends with Alucarda attempting to seduce Father Lázaro during confession. Lázaro and the nuns, horrified by this, engage in a mass flogging of each other as punishment for their failure to save the girls from demonic influence. After, Lázaro concludes they must perform an exorcism of Justine, who has grown progressively ill. During the exorcism, they bind Justine to a cross and poke at her flesh with instruments, eventually causing her to bleed to death. Dr. Oszek, arriving to examine Justine, walks in on the exorcism and is horrified by what he sees. Deeming the practice archaic and sadistic, Oszek takes Alucarda with him, fearing for her life.
Alucarda awakens in Dr. Oszek's home, frightened and confused, and is comforted by his blind daughter, Daniela. Meanwhile, Oszek is summoned back to the convent, where the nuns have found that Justine's corpse has disappeared. Upstairs, Sister Germana is found inexplicably burned alive. When her body reanimates, Father Lázaro bludgeons and ultimately decapitates her. The event challenges Oszek's science-based beliefs, and he flees back home, fearing for Daniela's safety; upon arriving, he finds Alucarda and Daniela are both gone.
Oszek is led to the abandoned crypt by the nuns, who suspect Alucarda might have gone there. Inside, Sister Angélica finds Justine's body lying in a blood-filled coffin. Now a vampire, Justine attacks Sister Angélica, but Angélica manages to stop the attack by praying. Oszek interjects and pours holy water on Justine, driving her into a fit, and she bites Angélica's neck before disintegrating. Followed by Oszek, several monks carry Angélica's body back to the convent, where Alucarda has arrived with Daniela. Using supernatural powers, Alucarda begins destroying the convent and causing various clergy to spontaneously combust in the grotto. Upon witnessing Angélica's corpse, Alucarda is suddenly overcome with sorrow, and goes into a fit of rage at the base of a burning crucifix in the chapel. After she collapses, Alucarda's body disappears into the ground as Father Lázaro and Oszek look on.