An American occult novelist battles to save the soul of a young girl from a group of Satanists, led by an excommunicated priest, who plan on using her as the representative of the Devil on Earth.
An excommunicated priest sets up a satanic cult that only looks Catholic on the outside. He convinces a man to sign over his daughter's soul so that she will become the devil's representative on earth on her eighteenth birthday, but as that day nears, the man seeks the help of an American occult novelist to save his daughter, both physically and spiritually.—Brian J. Wright <[email protected]>
Father Michael (Christopher Lee) is excommunicated from the church for heresy, although he does not recant.
20 years later in Bavaria, Father Michael collects a nun Catherine (Nastassja Kinski) from a nunnery and hands her to George (Michael Goodliffe) and Eveline (Eva Maria Meineke) who take her to the airport for a flight to London. George and Eveline then go to their hospital and greet a pregnant woman Margaret (Isabella Telezynska).
In London, John Verney (Richard Widmark) is launching his latest book about the occult at an art exhibition. Present at the launch are lovers Anna Fountain (Honor Blackman) and David Kennedy (Anthony Valentine). Henry Beddows (Denholm Elliot) arrives insisting he speak to Verney, and during their lengthy conversation he hands Verney an envelope in which there is a picture of his daughter Catherine. Verney heads to Heathrow airport to collect her. At Heathrow, Catherine's companion Kollde (Constantin de Goguel) telephones Henry but Henry does not answer; instead he is loading a gun while the phone rings. Verney collects Catherine behind Kollde's back and takes her to his home in London.
Later Catherine talks to her father on the telephone. While she does Kollde arrives at Henry's house with a gun. After a short scuffle, Henry shoots and kills Kollde.
Father Michael arrives at George and Eveline's hospital where Margaret is in labour. She is tended to by the three of them but she is tied to the bed and her legs bound together.
Anna and David telephone Verney to ask about the woman he collected from the airport. They arrange to meet at Verney's home the following morning.
While Margaret is in labour in Bavaria, Catherine suffers similar pains in bed in London. After Margaret's baby is born, Father Michael and George put Margaret to death with a lethal injection. Father Michael, George and Eveline bring the new born baby to England.Anna and David arrive at Verney's house. Verney explains that Satanists are after Catherine and her father Henry is trying to protect her and trusted her to Verney since he is an occult expert.
Meanwhile Father Michael explains to George and Eveline that it is too late for Henry because he took a pact 18 years earlier. Father Michael telephones Henry and as they talk, Father Michael wraps a cord around the telephone. At the other end, Henry sees a snake around his wrist and in his horror reveals Catherine is at Verney's home.
In a flashback to 18 years ago, Henry secretly witnesses Catherine's birth in a church in a Satanist ritual conducted by Father Michael. During the birth his wife and Catherine's mother Isabel (Anna Bentinck) dies. Henry's hiding place is revealed and he is forced to take a pact: a satanic pendant.
Father Michael, George and Eveline conduct another satanic ritual which has the power to make Catherine put on a satanic pendant and leave Verney's home. Verney arrives back just in time to see Catherine leaving and stop her, ripping off the pendant. Catherine explains she had a vivid dream in which she was part of a satanic ritual. Catherine becomes more and more hysterical until Verney slaps her and knocks her out.
Father Michael telephones Verney to tell him Henry is in hospital to try and get Catherine back but Verney refuses. Verney visits a bishop at St. Paul's cathedral who explains that Father Michael was excommunicated because he wanted to create a personification of a god but it was actually the personification of the devil called Astaroth. Verney checks the pages Father Michael has read in a book about Astaroth in the cathedral's vaults.
Meanwhile, while David tries to locate Henry, Father Michael uses his power to make Catherine stab Anna and flee Verney's home. She is found on the streets by George and taken to Father Michael and the new born baby. Eveline starts donating her blood to be used in the baptism.When Verney arrives home, David insists they go and look for Catherine together. Verney and David search Henry's home and find the body of Kollde. Continuing the search, they find Henry weeping and hysterical in a chair. Verney explains they are planning to baptise Catherine and she will become Astaroth. They want Henry to tell them where Catherine has been taken but he won't without the pact. As they drive away, Verney explains to David that the Satanists baptise a child in the blood of her dead mother, bring her up in seclusion as a nun, then baptise her again with blood as the devil.
Verney and David arrive at a church where they see a vision of Catherine's mother on the altar. Verney searches the altar for the pact but as he finds it, David grabs it. David is immediately consumed in fire and dies in a pile of ash.
Eveline dies providing all her blood for the baptism of Catherine.
Verney returns the pact to Henry, who then reveals where Father Michael will have taken Catherine.
Father Michael has placed Catherine on an altar and surrounded her with a circle of blood. Verney arrives to see Father Michael sacrifice the baby. He overpowers George with a flint stone which causes Father Michael to pause the baptism. Verney explains that the demons are angry with Michael, although Michael thinks he is safe because of what he read in the book of Astaroth. However, Verney has the flint with the blood of George, one of Michael's disciples, on it which will actually protect Verney. He steps inside the circle of blood surrounding Catherine, throws the flint at Michael knocking him to the ground, and carries Catherine out of the circle. When he looks back, Michael and the circle of blood have disappeared.
