David Niven plays Jeff Carleton. A gambler with a death wish. As he went to fight in the civil war, he lost his wife and children.
Carleton cheats at cards in the hope that someone would shoot him dead. His opportunity comes but the Sheriff steps in.
Later some settlers come down looking for a preacher. One of them is looking for his dying mother.
They take Carleton. He looks like a preacher and he can read the bible.
Later revealed as a gambler, Carleton uses his card skills to get a guide for the wagon train. It also gives Carleton a chance for redemption.
Niven does not convince as southerner, unless he is someone from the south of England. However he does carry his character's story with conviction.