Actress Chris MacNeil becomes increasingly disturbed by the inexplicable behavior of her 12-year-old daughter Regan--mouthing obscenities, predicting the murder of one of Chris's friends, and urinating in public. Doctors and psychologists have no explanation and as a last option, Chris consults a priest. Father Damian Karras, a Jesuit who is having doubts about his own faith following his mother's death, investigates. Karras comes to no other conclusion that Regan is possessed by a demon. Father Merrin, an older Jesuit, helps Father Karras perform an exorcism, battling the demons inside the child. As much a film about Catholicism and the crisis of faith in the modern world as possession, the Exorcist remains a brilliant horror film, one with an archetypal ability to reach and disturb viewers.