Jonas Nightengale is a fraudulent Christian faith healer who makes a living travelling around America holding revival meetings and conducting 'miracles' with the help of his friend and manager, Jane, and their entourage. One of their trucks breaks down in Rustwater, a town in desperate need of rain to save their crops. While waiting for spare parts, Jonas decides to hold a revival meeting in the town. The local sheriff, Will Braverman, is skeptical and tries to prevent his town and its people from being conned. However a local disabled boy, Boyd, believes Jonas could make him walk again. Events in Rustwater make Jonas examine his own faith and doubts.