Mrs. Dubose is referring to Atticus' defense of Tom Robinson. Her declaration that he was going against his raising directly relates to Simon Finch, and the fact he was a slaveowner. The fact that <u>Atticus followed his own heart, values, and sense of morality</u> was a good thing.
The plot of the story refers to the chain of related events which explain what happens in a story. In every story plot, there is most usually a conflict.
The entire premise of the story is that two men are hunting each other on account of hatred derived from a centuries old land dispute. Society Notwithstanding the ingrained hatred the two men have for each other, they recognize the societal constraints placed on would-be-murderers.