Under the influence of the demonic-or epilepsy, as skeptics insist-Emily Rose convulses, shrieks, and shreds walls. Her body alternately collapses and goes rigid with contortions. In the throes of her torment, and during the exorcism, she suffers fatal injuries.
Academy Award nominee Tom Wilkinson plays Father Moore, the priest blamed for Emily Rose's death. He goes on trial for negligent homicide and the resulting proceedings pit faith against science.
For his part, the prosecutor asserts that Emily Rose was never demon possessed. In the trial, he mocks Father Moore's beliefs in the demonic and accuses the pastor of neglecting the young woman's medical needs in favor of the exorcism.
"Father Moore's beliefs are based on archaic and irrational superstition," said the prosecutor, himself a Christian. "I'm a man of faith and a man of facts. And in here facts are what matter."
Father Moore's defense attorney, Erin Bruner (played by Oscar nominee Laura Linney), is an agnostic who assumes professional and a personal risk when she defends the priest by arguing for the authenticity of demon possession and exorcism. In a dramatic coda to the trial, Father Moore reads a letter from Emily Rose, who believed she was possessed and wanted her story told. "People say that God is dead, but how can they think that if I show them the devil?" she says in the letter.
Craig Detweiler, a screenwriter, author, and film professor at Biola University, has been friends with Derrickson since the two attended film school together. Detweiler said his friend has figured out how to combine deep philosophical questions with a mainstream Hollywood format, which he called a remarkable balancing act.
"Most films try to enlighten or entertain,'' Detweiler said. "It's the rare film that manages to do both seamlessly and simultaneously."
Researching the film was a scary and oppressive experience, Derrickson said, adding that he would never again study such subject matter. To him, demons are absolutely real.
"My belief in it comes not so much in theological or religious conviction, but empirical evidence in the documented cases out there coupled with things I've seen and experienced," Derrickson said. "If you really look hard at the evidence, the most rational conclusion is to believe that the demonic is real."
But rational people also deny that demons exist, Derrickson said. Thus, "The Exorcism of Emily Rose" posits opposing points of view. A movie that deals with issues as volatile as religious belief must respect an audience's multiple perspectives, he said.
"No matter what you believe this movie will challenge you in some way," Derrickson said. "I don't know how you can watch it without coming away and asking yourself, or the person you saw the movie with, what you believe about the reality of the demonic, and therefore the existence of the devil and the existence of God."