The Exorcist begins with a series of strange and unexplained events surrounding a young girl named Regan MacNeil (played by Linda Blair). Regan is a 12-year-old girl who is the daughter of a single mother, Chris MacNeil (played by Ellen Burstyn). Chris is a famous actress who is filming a movie in Rome, and she takes Regan with her. However, things take a dark turn when Regan becomes possessed by a demon.