Three of the main characters in Harper Lee's To Kill a Mockingbird are Jem (Jeremy) and Scout (Jean Louise) Finch, and Dill (Charles Baker) Harris. The three children spend most of their time together during the summers while Dill is in Maycomb visiting his aunt. They act out stories, they try to catch the attention of their reclusive neighbor Boo Radley, and occasionally they get in trouble for doing things they should not do.
On the night before the three kids go to the jail, Sheriff Heck Tate comes to call on Atticus; outside are other men from town who are sharing their concerns about Tom Robinson's safety. Robinson is being moved to the Maycomb jail tomorrow night, and there have been threats of violence made against him. The kids do not understand everything they hear, but they sense the uneasiness everyone but Atticus seems to feel.
The next night, after dinner, Atticus tells Jem and Scout good-night earlier than usual because he will be gone when they go to bed. This is just the kind of opportunity the adventuresome kids do not want to miss, so they sneak out after they have supposedly gone to bed. Jem and Scout pick up Dill and they walk through town looking for Atticus, though they do not really know where he is or what they might find. They had no intention of going to the jail; they simply do not want to be left out and the jail is where all the action in Maycomb is tonight.
At the jail, Atticus sits calmly right below the window of Tom Robinson's jail cell and reads; a clan of Cunninghams has gathered to cause trouble, though the children do not realize the potential danger of the situation. A slight physical confrontation ensues, but no one is hurt.
In the midst of this strange assembly, Atticus stood trying to make Jem mind him. “I ain’t going,” was his steady answer to Atticus’s threats, requests, and finally, “Please Jem, take them home.”
Jem is older and realizes what is happening, but he refuses to leave. As it turns out, their presence (especially Scout's) at the jail that night is the very thing that diffuses the tense situation.