Supernatural - Season 5, Episode 17, 99 Problems
As Sam and Dean arrive in a small town they discover it is under demon attack. Strangely the daughter of the local pastor is having visions and is giving guidance to the townsfolk as a prophet. Guiding them and advising them she has built up their trust and blind faith. But things are not what they seem as Sam and Dean discover the truth when Castiel shows up.