Kill, Baby, Kill (Italian: Operazione paura, lit. 'Operation Fear') is a 1966 Italian gothic horror film directed by Mario Bava and starring Giacomo Rossi Stuart and Erika Blanc. Written by Bava, Romano Migliorini, and Roberto Natale, the film focuses on a small village in the early 1900s that is being terrorized by the ghost of a murderous young girl.
Overseen by one-time producers Nando Pisani and Luciano Catenacci of F.U.L. Films, Kill, Baby, Kill was considered to be a small-scale project compared to Bava's earlier films, as its was made without internationally-recognized stars or the support of a major distributor. Although a complete script was written by Migliorini and Natale prior to the start of production, Bava claimed that much of the film was improvised. Shot partially on location in Calcata, Faleria and at the Villa Lancellotti in 1965, the film underwent a troubled production due to F.U.L. Films running out of money during principal photography, prompting the cast and crew to finish the film in the knowledge that they would not be paid for their work. In post-production, the score had to be compiled from stock music created for earlier film productions.
Although the film's commercial performance during its initial Italian theatrical release was limited, its domestic run outgrossed those of Bava's previous horror films; abroad, it garnered positive notices from Variety and the Monthly Film Bulletin. With the re-evaluation of Bava's filmography, Kill, Baby, Kill has been acclaimed by filmmakers and critics as one of the director's finest achievements; it was placed at number 56 on a Time Out poll of the best horror films.
In 1907, Dr. Paul Eswai is sent to the Carpathian village of Karmingam to perform an autopsy on Irena Hollander, a woman who died under mysterious circumstances in an abandoned church. Monica Schufftan, a medical student who has recently returned to visit her parents' graves, is assigned as his witness. During the autopsy, they find a silver coin embedded in Hollander's heart.
The local villagers are accustomed to medicinal practices and superstitions Eswai finds preposterous, and claim that Karmingam is haunted by the ghost of a young girl who curses those she visits. After Nadienne, the daughter of local innkeepers, is visited by the girl, a ritual to reverse the curse is performed by Ruth, the village witch. That evening, Eswai goes to meet with a colleague, Inspector Kruger, at the villa of Baroness Graps. When he arrives at the large, decrepit house, the Baroness informs him that she knows of no such Kruger. Upon leaving, Eswai encounters the ghostly young girl.
Meanwhile, Monica has a nightmare about the child, and awakens to find a doll at the foot of her bed. She runs into Eswai in the street, and he offers to take her to the inn so she can sleep. At the inn, Eswai discovers that Nadienne is wearing a leech vine around her body as part of Ruth's treatment. Believing this procedure to be causing her greater suffering, he removes the vine despite her family's concerns. In the local cemetery, Eswai finds two gravediggers burying Kruger's corpse, who has been shot in the head. Simultaneously, Nadienne is awoken by the young girl at her window, who compels her to impale herself with a candelabra.
Eswai and Monica are informed by Karl, the burgomeister, that the ghostly girl is Melissa Graps, the dead daughter of the Baroness, and that she is responsible for the deaths of Hollander and Kruger; he also reveals to Monica that the Schufftans were not her real parents. When he goes to retrieve evidence proving so, he is compelled by Melissa into destroying the documents and killing himself. Turned away by Nadinne's father due to her death, Monica and Eswai attempt to get the reluctant villagers' attention by ringing the church bell. Inside the church, they find a secret passageway, where Monica experiences déjà vu. They discover the Graps' family tomb, which includes that of Melissa, who died in 1887, aged seven.
They find a staircase leading out of the tomb, which takes them inside the Villa Graps, where the Baroness confronts them in the hallway. She reveals that Melissa was trampled to death while fetching a ball during a drunken festival. Melissa appears in the room, and Monica suddenly vanishes through a doorway. Eswai chases after her through a repeating series of doorways; in his pursuit, he confronts a doppelgänger of himself, after which he is left locked in a room and subsequently spirited out of the villa. He loses consciousness, and awakens in Ruth's home. Ruth explains that the coins found in the hearts of the victims have been placed there by her as talismans to ward off supernatural powers of the Baroness, who has invoked her daughter's ghost to punish the villagers, and that she intends to kill the Baroness to avenge Karl, who was her lover.
In the villa, the Baroness reveals to Monica that she is her daughter, and Melissa her older sister; following Melissa's death, the Baroness' servants, the Schufftans, sent Monica to be raised and educated in Gräfenberg for her protection. Melissa's ghost appears, chases Monica down the staircase into the tomb, and urges her to throw herself from a nearby balcony. Ruth arrives and confronts the Baroness. The Baroness stabs her through the chest with a fire poker, but Ruth manages to strangle her to death before dying, thus laying Melissa's soul to rest; Eswai arrives in time to save Monica. Reunited, the pair leave Villa Graps as the sun rises in the distance.