In a small Louisiana town, a series of biblical plagues start occurring, baffling the local population and attracting worldwide media attention. Katherine Winter, a former Christian missionary who lost her faith after a tragic family ordeal and who has since become a professor specializing in debunking religious phenomena, is called upon to investigate the mysterious events. Skeptical of anything that cannot be scientifically explained, Katherine, along with her partner Ben, sets out to find a logical explanation for the phenomena.

Upon arrival, Katherine and Ben encounter a tight-knit community that is both terrified and protective of a young girl they believe is behind the plagues. The girl, living as an outcast at the edge of the river, is surrounded by myths and rumors of her supposed supernatural abilities. As Katherine delves deeper into the mysteries of the town and the strange occurrences, her scientific beliefs are challenged. Personal demons from her past are unearthed, and she is forced to confront her own convictions about faith, forgiveness, and the nature of the supernatural, all while racing against time to uncover the truth behind the plagues before they claim more lives.