In Harper Lee's, "To Kill A Mockingbird," Tom Robinson is a Black man accused of beating and raping a white girl, Mayella Ewell. Atticus Finch is appointed to defend Tom. After the trial begins and the people in the community hear that Atticus in Tom's lawyer they get angry. In chapter 15, Atticus goes to the jail at night to protect Tom from anyone who might lose their sense of right and wrong. While he is sitting outside of the local jail door, a group of angry men approach him and want Atticus to turn Tom Robinson to them.
Unknowing to Atticus, Dill, Jem, and Scout followed Atticus to the jail. When the mob began to threaten Atticus the children came out of hiding. Atticus told all of the children to leave, but Scout stepped out and spoke to the crowd of men.
Scout defuses a tense situation by talking directly to Mr. Walter Cunningham—a member of the mob—and reminding him of his ties to the Finch family. She reminds him that his son Walter is her classmate. Mr. Cunningham orders the mob to get going.
The scene at the county jail is tense because Tom Robinson, who has been accused of raping Mayella Ewell, is being held there. Atticus anticipates trouble with some townspeople and decides to sit on the porch outside the jailhouse.
As he expected, a mob of white men arrives to take the law into its own hands. They clearly intend to take Tom Robinson, by force if necessary, and administer their own justice. Against their father's orders, however, Jem and Scout go to the jailhouse where they encounter the angry mob. Scout, too young to understand what is happening, recognizes Mr. Cunningham, the father of one of her classmates, and strikes up a conversation with him.
This small act humanizes Mr. Cunningham; he becomes ashamed of his behavior and convinces the other men to leave peacefully.