加入教会不久的年轻修女安，深信替人驱魔是她天生的使命，然而天主教会却有个令她不满的不成文传统：只有神父可以进行驱魔仪式。幸好，安和一个认可她驱魔天赋的导师相遇，因而破例让她参与并旁观驱魔课程，成为首位学习驱魔仪式的修女。安很快地展现出在驱魔上的才能，与此同时，众人却发现她与恶灵有着一段不可告人的过去……
Sister Ann (Jacqueline Byers) believes she is answering a calling to be the first female exorcist... but who, or what, called her? In response to a global rise in demonic possessions, Ann seeks out a place at an exorcism school reopened by the Catholic Church. Until now these schools have only trained priests in the Rite of Exorcism - but a professor (Colin Salmon) recognizes Sister Ann's gifts and agrees to train her. Thrust onto the spiritual frontline with fellow student Father Dante (Christian Navarro), Sister Ann finds herself in a battle for the soul of a young girl, who Sister Ann believes is possessed by the same demon that tormented her own mother years ago. Determined to root out the evil, Ann soon realizes the Devil has her right where he wants her.
