This novel examines the effects of the Civil War on Susan and her family as well as the people of Richmond, Virginia. Most people in Richmond were on the side of the South (Confederacy), so they didn't like Yankees (people from the North).
Susan also has a conflict with her mother who torments Susan by calling her names such as "Yankee brat". Susan responds to her mother's behavior by selflessly giving to the Southern cause, nursing sick soldiers. Susan becomes the opposite of her mother by her honesty, compassion for others, and not feeling the need to show off or thinking she's better than others.
The Civil War itself helps Susan mature, opening up her eyes to the good and evil in the world. She learns to stand up for what she believes in by giving her balloon to the North and becoming a traitor to the South. Through this act, she expresses the main theme of ". . . do what you think is right. Even if it hurts those around you. Those you love." With her maturity, Susan also learns to forgive her mother, and her relationship with her brother becomes stronger.
By the end of the novel, Susan is able to answer serious issues of the Civil War, such as looking at the consequences of slavery. As a result, Susan matures as a result of her conflicts and learns valuable lessons about herself, her relationship with her family, and life.