It's about a guy called Marjoe Gortner, (anagrams of which include the oddly appropriate Amen Terror Jog) who became famous-ish as a brimstone preacher at four years old! Having the ferver inducing routines and mannerisms forced into him by unloving hypocrite parents who made sure he was used to exploit as much money as possible from gullible audiences of backwards God-people.
Now in his late twenties, very much a non-beliver and a bit skint, Marjoe (Mary + Joeseph. Yup.) decides to go back into the preach-tents to spread the good word and hold open the donation sacks. Before the tour he arranges to have a documentary crew record both the on-stage performances and the off-stage confessions.
There's an odd moral ambiguity, apparently Marjoe had a crisis of concience, hence the documentary crew, however at one point he's seen happily singing to himself as he counts the money taken from that evening's punters. Either way, it's a fascinating watch and although forty years old, probably still relevant, the USA being a country that wouldn't dream of electing a president who doesn't give praise to God in their speeches.
Marjoe went on to appear in some terrible films where his excellent preacher acting skills seemed to desert him entirely, including Starcrash which we watched back in April.
If you haven't seen either, a double bill of this film followed by The Last Exorcism would make for a great theme night.