Cast: Ellen Burstyn, Max von Sydow, Jason Miller, Linda Blair, Lee J. Cobb, Kitty Winn, William O’Malley, Jack MacGowran, Barton Heyman, Peter Masterson, Rudolf Schundler, Gina Petrushka, Mercedes McCambridge, Eileen Dietz, Robert Symonds, Arthur Storch, Thomas Bermingham, Vasiliki Maliaros, Titos Vandis, Wallace Rooney, Ron Faber, Donna Mitchell, Roy Cooper, Robert Gerringer, John Mahon
At an archaeological dig in Iraq, Father Lankester Merrin (von Sydow) cleans a dirt-encrusted relic and discerns a sculpted image that disturbs him. Later, walking in a dusty town, he narrowly avoids being run over by a horse and cart. Returning to the dig in the desert, Father Merrin approaches a newly unearthed object, a statue of the demon Pazuzu, and hears a noise of an evil nature. In Washington, D.C., Chris MacNeil (Burstyn) lies in bed, reading a movie script. She hears a scratching noise from outside her room and goes looking for the source. On the dark hallway, as she passes the attic hatch, she hears the noise again. She enters Regan’s (Blair) room and sees that the window is wide open and her daughter’s bed covers are pulled away. Chris shivers as she closes the window and again hears the strange noise. She tucks her daughter in. The next morning, Chris tells Karl (Schundler), her Swiss butler, that there are rats in the attic. He says he’ll get some rat traps. Chris is an actress, working on a movie being filmed nearby at the University of Georgetown. She banters with the movie’s Director, Burke Dennings (MacGowran). As filming begins and Chris acts out her scene, a young Jesuit Priest, Father Damien Karras (Miller), looks on. When Chris returns to her house she handles business matters with her live-in personal assistant, Sharon (Wynn), and plays with Regan, who has found a Ouija board and an imaginary friend, Captain Howdy. At the University of Georgetown’s campus bar, Father Karras tells another Jesuit priest (Bermingham), the University President, that he wants out of his assignment, which involves psychiatric counseling. Karras is troubled by the issues of his patients, matters of faith and vocation, and wants to be closer to his mother, who is ill. Regan begins to behave oddly, and one night shows up in Chris’s bed, telling her that her bed was shaking. Chris investigates and tracks a crashing noise to the attic. She and Karl confirm there are no rats there. Nearby Dahlgren chapel is desecrated, a statue of the Virgin Mary despoiled. Chris takes Regan to Dr. Klein (Heyman), who diagnoses a nervous condition and hints at a psychological problem. During a party at Chris’ home, Chris asks Father Dyer (O’Malley) about Karras and learns that Karras’ mother has died. Regan returns to the party after being put to bed and urinates on the carpet in front of the guests. The guests leave and Chris bathes Regan and puts her to bed. That night Chris hears a loud noise. She enters Regan’s room and sees her bed shaking. Chris is horrified when the bed, with Regan on it, rises from the floor. Chris consults with physicians who carry out extensive medical tests on Regan as her condition rapidly deteriorates. The tests are inconclusive and Regan is returned home. She has to be sedated when she undergoes frightening personality changes and becomes violent, pushing Dr. Klein across her room with abnormal strength and cursing in a hoarse voice unlike her own. Regan is taken to the Barringer Clinic, and after all treatments fail, the physicians tell Chris that Regan suffers from sonambuliform possession and that undergoing the shock of an exorcism may reverse her condition. Distraught, Chris takes Regan back home. One evening, Regan is left in the care of Burke. He is gone when Chris and Sharon return. Burke is later found dead, and Chris is questioned by Police Lieutenant Kinderman (Cobb), who is investigating Burke’s suspicious death. Chris realizes that Regan is somehow to blame for Burke’s death. She approaches Father Karras, tells him about Regan’s condition, and asks him about performing an exorcism. He tells her exorcisms are not done anymore, but agrees to see Regan. Shaken by Regan’s vile words, Karras at first thinks she is suffering from a psychotic malady. He rejects Chris’ request for an exorcism. Lieutenant Kinderman watches Father Karras’ visits to the MacNeil home and tries to learn what is going on, but Karras tells him little. Confronted with Regan’s unexplained strength and malevolent knowledge, Father Karras relents and asks church officials for permission to perform an exorcism. The Bishop (Rooney) authorizes an exorcism and summons Father Merrin to lead the effort, with Father Karras’ assistance. Father Merrin arrives at the MacNeil house at night, carrying a weather-beaten valise. He meets Chris and Father Karras and says that they should begin at once. Father Merrin warns Karras to avoid conversation with the demon that possesses Regan. When Father Karras begins to describe the different personalities Regan has manifested, Merrin cuts him off. “There is only one,” he says. Dressed in vestments, carrying Roman Catholic Rituals, the priests enter the room where Regan lies, tied to her bed, the demon (McCambridge/Dietz) in her making horrible growling sounds. “Our Father who art in heaven...,” begins Merrin. The priests engage in battle against a manifestation of absolute evil, their lives and their souls, as well as Regan’s, at stake. Mike Oldfield’s instrumental, Tubular Bells, serves throughout the film as a chilling leitmotif for eeriness and danger. Based on the novel of the same name by William Peter Blatty.