Forty years ago, the demon was denied its prize. Now it will stop at nothing to destroy Angela Rance and her family.

Tomas, Marcus and Mother Bernadette race against time to defeat the demon, and the Rance family find themselves drawn into the conflict.

On the eve of Pope Sebastian's visit to Chicago, Marcus and his companions race to avert a potential tragedy. Tomas is offered a life-changing opportunity, but will the sins of the past endanger his future within the church? Meanwhile, as the Rance family attempts to recover from their most recent ordeal, a new problem threatens to tear them apart.

A visit to the foster home carries deadly consequences, as Marcus and Father Tomas attempt to draw the demon out of hiding. Rose finds herself the target of the demon's wrath. And no one suspects that a new danger may be lurking in the woods, waiting for its moment to strike. Meanwhile, Father Bennett and Mouse take the fight directly to the conspiracy as they attempt to hunt down an old adversary.

Kat struggles to confront the realization that her friend, Julia, is dead. Shopping for a dress to wear to Julia’s memorial service, Casey is given a sexy, expensive and slightly inappropriate dress by a salesman at the store. Seeking permission to conduct an exorcism, Marcus and Tomas take footage from the Rance home to papal emissaries, only to be met with shocking news that will change Marcus' life forever

Everything has led to this moment. As one priest fights for his life in the hospital, another is forced to confront the ghosts of his past. With time running out to save Andy's life, one of the exorcists must make the ultimate sacrifice.

Six months after leaving Chicago, Father Tomas and Marcus Keane's travels lead them to a troubled young woman in rural Montana. On a secluded private island off the coast of Seattle, Andy Kim runs a group home for at-risk foster children, whose lives are disrupted when the state sends a social worker.

Tomas and Marcus attempt to finish Cindy's exorcism and escape the wrath of her family. Rose conducts her inspection of Andy Kim's household.

Marcus and Tomas travel to Seattle where they find a young girl targeted by a force of pure evil. Meanwhile, Father Bennett tracks down a rogue church operative named Mouse who is waging a one-woman crusade against the demonic conspiracy.

When Bishop Egan denies Tomas permission to perform the exorcism on Angela's daughter, Father Marcus breaks out of Saint Aquinas and joins forces with Tomas, though he urges him to get his ex, Jessica, out of his life and heart. The Rance family's relationship with the demon deepens and when Marcus catches Angela stealing holy water, he instructs her on how to use it. On Chicago's south side, a series of bizarre ritual killings begin taking place.

As the exorcism begins, the fate of the foster home hangs in the balance. This is an adversary unlike anything Marcus and Tomas have ever faced, and in order to save this family, the two of them must journey into the mouth of madness itself.

Something is wrong in the Rance household. Angela Rance suspects demonic possession and enlists the help of two priests: the progressive, but naive Father Tomas Ortega and the broken holy warrior, Father Marcus Keane. Together they will be drawn into a nightmare beyond imagination.