Actress Chris MacNeil (Ellen Burstyn) lives in upscale Georgetown, suburb of Washington D.C. with her daughter Regan (Linda Blair ). Now Chris is working on a new movie and her time is being spent on her career. Her daughter Regan is about to make her life a living hell.
Father Merrin (Max Von Sydow) is on a dig and finds some interesting artifacts. All leading to terrible things to come. He also is a scholar in Exorcisms. Father Damien Karras (Jason Miller) is a local priest to Chris and her home. In a short time all of these people will be involved in something that no one wants to explain.
You see there are things that are about to occur that man cannot explain. Regan is a twelve year child. She has been feeling depressed and quiet. Her mom thinks its because of the time that she has been spending on the set. One night Chris is having some guests over for drinks and appetizers. Regan is in good spirits and when it's time to go to bed she goes quietly to her room. A little while later she has come back down to the party and starts to urinate on herself and the floor. Big time party breaker. Chris cleans her daughter up and puts her back in bed. A while later Chris hears voices and noises coming from her daughters room. When she opens the door she see her daughters bed levitating and Regan floating in the air. Chris jumps on the bed but it continues to levitate.
Chris has Regan evaluated by some doctors and they find nothing physically wrong. They suggest a shrink but that doesn't help. Chris starts noticing a priest hanging around the set and following her home. It's Father Karras and he needs to talk to her. He asks questions about Regan's behavior and Chris is astonished at the questions.
Later that night Chris is once again called back up to Regan's room and finds her daughter using a cross and ramming it into her vagina. Chris is mortified. Chris finds Father Karras and confides in him about what's been happening.
A friend of Chris's was on the way over to talk to her when he is found dead outside her townhouse. Police Lt. Kinderman comes to the door to ask some questions about the death. In reality it was Regan or the demon inside that killed the man.
Finally, Father Karras wants to call in Father Merrin to see if an Exorcist is needed. What happens next will make your skin crawl but unfortunately you must watch the movie to find out what the Devil has planned. This is one of the best horror movies ever made. Director William Friedkin has put a masterpiece from hell together that is above all the rest. Watch Regan fight God and the Devil in one of the best movies ever made. " Damien why you do this to me".