At the end of the novel, Atticus reads to scout as she drifts off to sleep. How does the topic of the story connect to one of the novel's major themes?

Scout falls asleep while Atticus reads to her, and wakes up while he carries her to bed. She tells him she was listening all the time, and that the book is about a character who was chased and caught and then found to be innocent and "real nice." Atticus tells her, "most people are, when you finally see them." Atticus then spends the rest of the night by Jem's side. The story relates to the theme of the mockingbird...... and and both Boo and Tom's stories.