In a small town in Louisiana, the life of supernatural phenomena expert Katherine Winter takes an unexpected turn when she is called to investigate a series of strange events that seem to be linked to an ancient legend. Karnak, the town in question, is the scene of plagues and inexplicable disasters: frogs, locusts, and diseases ravage the population, and many believe these events are signs of the apocalypse.
Katherine, who has lost her faith after the death of her daughter, initially arrives with a scientific mindset, dismissing rumors of possible divine punishment. However, as she delves deeper into the mystery, she begins to uncover unsettling truths about the town's history and its inhabitants. Accompanied by her assistant Ben, she faces the despair of the locals, who are convinced that a girl named Loren, with supernatural powers, is at the center of it all.
As Katherine investigates, her skepticism is tested in the face of disturbing phenomena. What begins as a scientific inquiry transforms into a struggle to understand a world that seems to defy all logic, leading her to a direct confrontation with forces far more sinister than she ever imagined.
Tension escalates, and the secrets of the past are revealed, prompting Katherine to reconsider not only her beliefs but also her purpose, in a race against time that could have devastating consequences for everyone.