What is the plot of "Barn Burning" by William Faulkner?

Abner Snopes is charged with arson for burning down his employers barn.The opening scene shows him being tried in a makeshift courtroom inside a general store. The man and his son are acquitted because of a lack of evidence, and the two are insulted as they leave the courtroom. Over a fire that night, Ab accuses the boy of nearly admitting to burning the barn. The two start work at a new plantation owned by Mr. de Spain. As they settle in to their shack, a rug is brought which they ruin. Mr. de Spain demands payment for the item. Instead, Abner decides to burn de Spain's barn too. His son, Salty tells on his father before the act can be completed, and he leaves his father forever.