The Last Exorcism is an American horror film that was released in 2010. The film footage is supposed to be found footage that is discovered after the film's events have transpired. Reverend Cotton Marcus is at the head of this scary film. He is a disillusioned preacher who has long ago lost his faith following the birth of his seriously ill son. He has been performing exorcisms for quite some time on many people who are supposed to be afflicted by possession. The only issue is that these exorcisms are fake, and the people he performs them on are not truly possessed.
The reverend is horrified when he hears of the death of an autistic boy during an exorcism and agrees to expose the falsehoods behind the whole ordeal with the help of a documentary film crew. He randomly picks an exorcism to oversee for the purpose of the film, hoping to expose the falsehood behind the claims and the exorcism itself. The family he has chosen are a family of rural farmers who claim that their daughter is possessed and is slaughtering their farm animals.
Equipment is planted at the family's farmhouse so that the reverend can later prove to them that the entire thing was false. The reverend and the film crew leave feeling that all will be all right now and feel that the young girl has a mental condition, not a possession as her parents felt. Yet later that night the young girl that received the exorcism, Nell, shows up at the reverend's hotel room seeming not quite right. She is taken to the hospital but is found to be physically fine.
They find out from the hospital later that Nell is pregnant, and they accuse her father of incest. But is this really the case? Stranger and stranger events come to light, and the reverend must question if possession may be real after all.