坐落在路易斯安那州的巴顿鲁治郡,生活着一个名叫柯登·马可斯(帕特里克·法比安 Patrick Fabian 饰)的年轻牧师,他自幼跟随父亲学习圣经,其布道的风格独特,倍受欢迎,但与他来说终究只是一项营生;在家中柯登则是个好丈夫和好父亲,与妻儿过着幸福的生活。马可斯家族同 时也是有着丰富经验的驱魔世家,然而一些虚伪的驱魔仪式令柯登倍感苦恼。他于是请来摄制组拍摄纪录片,旨在揭露驱魔仪式中的骗人行径。 恰好此时,另一个州的艾凡伍家来信求助。柯登决定将其作为自己最后一次的驱魔,他和摄制组驱车前往,并顺利为女孩奈儿做了驱魔仪式。然而,一切并未就此结束,恐怖的事情接二连三发生……In Baton Rouge, Louisiana, the evangelical Reverend Cotton Marcus was raised by his father to be a preacher. He agrees that the filmmaker Iris Reisen and the cameraman Daniel Moskowitz make a documentary about his life. Cotton tells that when his wife Shanna Marcus had troubles in the delivery of their son Justin, he prioritized the doctor help to God and since then he questions his faith. Further, he tells that exorcisms are frauds but the results are good for the believers because they believe it is true. When Cotton is summoned by the farmer Louis Sweetzer to perform an exorcism in his daughter Nell, Cotton sees the chance to prove to the documentary crew what he has just told. They head to Ivanwood and they have a hostile reception from Louis's son Caleb. Cotton performs the exorcism in Nell, exposing his tricks to the camera, but sooner they learn that the dysfunctional Sweetzer family has serious problems.