What is the plot in Barn Burning?

The opening scene of "Barn Burning" finds the story's protagonist, a ten-year-old named Colonel Sartoris or "Sarty," waiting with his father, Abner Snopes, in a Southern small-town general store being used as a courtroom; the time is ten or fifteen years after the Civil War. As we learn from the interior monologue through which Faulkner conveys all of the story's events, Ab Snopes has been called into court on a charge of arson by his landlord-employer. (Ab is a sharecropper, someone who "rents" farmland by promising to remit part of his harvest to the property owner). Sarty is acutely aware of the physical aspects of the place, the aroma of the goods, the appearance of cans and jars on the shelves. His overwhelming thought is of an enemy, "ourn! mine and hisn both!" The reference is to the plaintiff. Faulkner underscores Sarty's sense of family loyalty to his father.