The two main plots in To Kill a Mockingbird concern the mysterious and unseen Boo Radley, and the children's attempts to get a glimpse of him (Part One); and the trial of Tom Robinson (Part Two). Author Harper Lee ties the two plots together at the end of the story when Boo Radley finally makes his first appearance, coming to Jem's and Scout's rescue when Bob Ewell--Tom Robinson's accuser--tries to kill them.
Among the other characters and subplots are:
- Miss Maudie Atkinson, Scout's confidante, whose house burns during an unseasonal snow in Maycomb.
- Mrs. Henry Lafayette Dubose, the meanest lady in the neighborhood, who decides to rid herself of her morphine habit before dying.
- Atticus Finch, Maycomb's finest attorney and representative to the state legislature, who reveals a talent unknown to his children when he kills a mad dog with a single shot between the eyes.
- Aunt Alexanda, Atticus' sister, who decides to come and stay with her brother in Maycomb because Jem and Scout need a more motherly influence in the household.
- Dill Harris, who comes to stay with his Aunt Rachel each summer and spurs Jem's and Scout's interest in Boo.