In "to Kill a Mockingbird," a group of men visit the home of Atticus Finch to tell him that they are not comfortable with his defense of the Negroe, Tom Robinson. They also demand that Atticus drop his defense of Tom, but Atticus replies that he will defend Tom to the best of his ability in order to see that truth is served in the courtroom. Enraged, the men move forward aggressively towards Atticus. Perceiving the tension, Jem tells his father that the phone is ringing.
Later in the Sunday afternoon, the children find their father sitting in front of the jail with an extension cord and a light on the end of it. A mob has formed and approaches the jail in an aggressive and menacing manner. With loyal perception, the children intervene; Atticus then orders them to return home, but they refuse. When one of the men threatens Jem, Scout approaches Walter Cunningham and speaks privately to him, reminding him of things that Atticus has done for him and the fact that his son is her classmate. Being an honorable man, Mr. Cunningham, Mr. Cunningham orders the mob to leave.
Evidently, the phone call that Atticus has received has alerted him to this confrontation, for Underwood has had the mob covered with his shotgun.