Scout lives in Maycomb with her older brother Jem and their widowed father Atticus, who is a lawyer. Jem and Scout befriend a boy named Dill, who visits his aunt in Maycomb every summer. One summer Atticus is chosen to defend Tom Robinson, a black man who has been accused of raping a young white woman, Mayella Ewell.
Atticus agrees to defend Tom despite being frowned upon by the other citizens of Maycomb. Other children taunt Jem and Scout for Atticus's actions, calling him various names, making it harder for Scout to understand her father's actions and why he wants to help someone who has commited a crime. The situation gets even harder, when violence, hatred and the rumors begins to spread through the city as the trial comes closer.
Scout, Jem and Dill are curious and eager to finding out what really happened, but Atticus does not want the three friends near the trial. How are they going to figure out the truth? Where is the difference between the truth and a lie? And how can this affect the difference between black and white, men and women and the rich and the poor?