The film was released on DVD in the USA on October 2, 2001.
William S. Bowdern (Timothy Dalton) is a World War II veteran who was severely affected by a bad experience in France on All Saints’ Day in 1944. In the first scene of the movie, we flash-back through one of Bowdern's dreams to where he was trying to escape from a German advance as SS soldiers execute wounded American soldiers. A wounded soldier calls Bowdern, the chaplain, to give him the Last Rites; Bowdern at first denies him so he can escape. Bowdern rethinks the matter and does his duty but is bayonetted by an SS soldier. He becomes an alcoholic, tormented by his injuries and the guilt of refusing a dying man's last wish.
Years later, Bowdern is teaching his students at St. Louis University (SLU) when, at the end of the lecture, an angry mob smashes the classroom's windows. When Bowdern gets out, he discovers that there is a demonstration against the school's recent racial integration. When the police arrive, he asks them to arrest "those people" — meaning the protestors — but the police arrest the black students instead. Angered, Bowdern physically attacks the cops, who arrest him as well. Father Raymond McBride (Henry Czerny) pays his bail, and drives him to the Alexian Brothers Hospital to show where the church places hopeless alcoholics and the mentally ill.
Robbie Mannheim (Jonathan Malen) is sitting with his aunt, Hanna (Piper Laurie), who is teaching him how to contact the ‘other world’. Robbie's mother (Shannon Lawson) suddenly discovers the two at the Ouija board. She scolds Aunt Hanna for disregarding her request that she not expose Robbie to such ideas. Robbie disobeys his mother's demands that he stay away from the supernatural, as he enjoys the contacts.
When Aunt Hanna dies, Robbie continues trying to reach the other world. One day one of Robbie's classmates (Sensei Jamie) during school is severely wounded in the hand when a desk falls on top of him. Robbie is blamed. Ultimately, he is expelled from school. His father (Michael Rhoades) demands to know why Robbie hurt his classmate. When Robbie explains to his father that he did not deliberately do that and the desk moved itself, his father does not believe him. During their conversation, the chair on which Robbie is sitting moves out from under him, making Robbie crash to the floor. Robbie's parents feel someone or something is trying to harm their child. They feel he may really be ‘possessed’.
They take him to the Lutheran Pastor Reverend Eckhardt (Richard Waugh), who understands what is happening to Robbie and takes him to his house to put him under exact monitoring (by putting him in a special room and attaching a light in front of his bed to help him record daily reactions by his camera). During Robbie's stay, several things occur that convince Pastor Eckhardt that Robbie is being afflicted by demons: strange noises are made in the house, the wall clock is smashed, and Robbie falls into fits of rage and hysteria. When Pastor Eckhardt tells his wife that Robbie should be treated by the Catholics, Robbie attacks him.
McBride visits the family in their house to check on Robbie after his parents go to the university requesting help. During one of Robbie's fits of hysteria, the parents find the letters SLU scrawled on his belly. When he enters his room, he is attacked and becomes convinced that the child is endowed with some sort of supernatural power, and convinces Bowdern to visit the family.
Bowdern visits Robbie in his room, comforting him with his knowledge of comic books. Bowdern notices that Robbie is interested in magic and ventriloquism, while Robbie notices that Fr. Bowdern is affected by his collection of toy soldiers that sets off a post traumatic stress disorder event. When Father Bowdern tries to convince the parents that there is nothing wrong with Robbie, the boy suddenly becomes hysterical, speaking in Latin as things fly across the room. Bowdern becomes convinced that Robbie must undergo treatment.
Bowdern and McBride go to Archbishop Hume (Christopher Plummer) to persuade him to give Robbie an exorcism. The Archbishop is skeptical, saying that he is trying to improve the Catholic Church's public image as a modern institution, free of ancient superstition. He requests to speak to McBride alone, and he nominates Bowdern to handle the issue.
Bowdern begins Robbie's treatment, assisted by McBride and Father Walter Halloran (Michael McLachlan). They conduct several visits to him during which Robbie starts throwing temper tantrums. He scratches at them, vomits and urinates on them, and swears uncontrollably. During the treatment trials, Bowdern has flashbacks to his war experiences and dreads that this may be another failure. Robbie is transferred twice to two different churches. Finally, Bowdern manages to cure him. The room in the church where the exorcism takes place is locked on Archbishop Hume's orders.Timothy Dalton as Fr. Willam Bowdern
Henry Czerny as Fr. Raymond McBride
Jonathan Malen as Robbie Mannheim
Michael Rhoades as Karl Mannheim
Shannon Lawson as Phyllis Mannheim
Christopher Plummer as Archbishop Hume
Piper Laurie as Aunt Hanna
Richard Waugh as Reverend Eckhardt
Michael McLachlan as Father Walter Halloran
Sensei Jamie as Robbie