What does the first scene of "o brother, where art thou" depict?

Three convicts, Ulysses Everett McGill, Pete Hogwallop, and Delmar O'Donnell escape from a chain gang and set out to retrieve a supposed treasure Everett buried before the area is flooded to make a lake. The three get a lift from a blind man driving a handcar on a railway. He tells them, among other prophecies, that they will find a fortune but not the one they seek. The trio make their way to the house of Wash, Pete's cousin. They sleep in the barn, but Wash reports them to Sheriff Cooley, who, along with his men, torches the barn. Wash's son helps them escape.