After a traumatic serial killer case and the loss of her husband and father, FBI agent Lauren Lamb turns her back on her brilliant career as a BAU special agent, and seeks a quiet life in her father's homeland of Italy. But after a string of unexplained, seemingly supernatural murders, the Vatican convenes a team to separate truth from fiction, and Lauren is needed. Teamed with an exorcist, Lauren must grapple with her faith as she investigates the mysterious death of a nun in an ancient cloister in Italy. Is something greater at work? Or is a killer stalking?