When a group of men, led by Mr. Cunningham, shows up at the Maycomb jailhouse the night before the Tom Robinson's trial, what have they come to do?

In Chapter 15, Walter Cunningham Sr. and the rest of the Old Sarum bunch arrive at the Maycomb County jailhouse to lynch Tom Robinson before his trial. Fortunately, Atticus is waiting outside of Tom's cell when they arrive. Atticus tells them to turn around and go home, and says that Sheriff Tate is around here somewhere. They tell Atticus that they called him off on a snipe hunt, which would allow them time to take Tom Robinson from the jail and lynch him. Seemingly out of nowhere, Scout runs out from behind Tyndal's Hardware store into the middle of the group of men. Jem and Dill follow Scout out of the shadows and Jem refuses to leave when Atticus tells him to go home. After numerous attempts to have a conversation with Walter Cunningham Sr., Scout successfully gains his attention. Walter Cunningham Sr. realizes Atticus' predicament and tells the men to head home. The Old Sarum bunch planned on lynching Tom Robinson that night but were unsuccessful.