Set against the backdrop of the Vatican's ancient atmosphere, the film follows Father Gabriele Amorth, a grizzled and seasoned exorcist who dedicates his life to battling malevolent demonic forces. Called upon by the highest echelons of the Catholic Church, Amorth faces his most daunting case yet when a young boy in rural Spain becomes possessed. The case takes on an ominous significance as details surface about the boy’s possession and its ties to a darker agenda threatening the Church itself. Tasked with uncovering the truth, Amorth allies with another priest, Father Esquibel, to delve into chilling secrets hidden within a mysterious ancient abbey.

As they confront increasingly terrifying paranormal phenomena within the grounds of the abbey, the two priests grapple with their own inner demons and faith. Their investigation reveals hidden caches of forbidden knowledge while leading them into the shadowy corridors of ecclesiastical power struggles. As Amorth works tirelessly to perform a traditional exorcism and protect those living in fear, tensions mount, pushing him towards a revelation that could shake the foundation of his beliefs. Facing the ultimate test of righteousness and resolve, Amorth's journey challenges not only his faith but also poses existential questions about the nature of good and evil. The escalating stakes demand swift intervention before darkness threatens to engulf the innocent and devour hope from the world of the living.