You don't tell us which episode you are talking about, but you have it tagged with Chapter 8, so I am going to assume you are talking about the fire that burns Miss Maudie's house.
When Atticus finds out about the fire, he wakes Scout and Jem and gets them out of the house in case the fire spreads to their own home. He ends up having them stand in front of the Radleys' house. This is important because, at the end of the episode, we find out that someone has put a blanket around Scout's shoulders. Atticus tells Scout that it was Boo who did it.