In the 1st part of the book, we are introduced to the protagonists Scout and Jem. The story takes place in the 1930s, in Maycomb, Alabama. Other important characters include Atticus Finch, Boo Radley, Tom Robinson, and Bob Ewell.
During a walk home from school, Scout and Jem find an oak tree in front of the Radley's house. They notice small objects inside, which they believe are gifts from Boo Radley. One day, they find the oak tree filled up with concrete.
Dill returns for the summer, and the kids get into more trouble with the Radley'. The children try to get a peek at Boo, but Mr. Nathan Radley hears them and shoots a gun to scare them away. During the getaway, Jem loses his pants, and when he goes back to get them, he finds them sown up and neatly folded. Jem suspects Boo Radley did him a favor.
Atticus is appointed as Tom Robinson's judge in an upcoming trial, when Tom is accused of raping Mayella Ewell, Daughter of Bob Ewell. Atticus clearly presents and proves that Tom is innocent, but the verdict is guilty anyway. Jem cries the night of the trial because of the injustice and unfairness towards Tom.
Bob Ewell Is angry that his daughter is caught lying, and swears revenge on Atticus. After Scout and Jem's Halloween pageant, Bob Ewell attacks them when they are walking home. Jem breaks his arm fending off the attacker.
Boo Radley then saves them by stabbing Bob to death. Boo Radley then carries Jem home and Scout accompanies boo on his way home. Atticus eventually finds out it was Boo, but Heck Tate steps in and convinces Atticus to say that Bob Ewell fell on his knife. This was, Boo was sage from harm.