In chapter 25, Scout recalls Dill's story about the day Atticus picked him and Jem up while they were walking home from Barker’s Eddy. After Jem and Dill waved Atticus down, he reluctantly agreed to give them a ride home but had an errand to run with Calpurnia, who was sitting in the back seat. Atticus then explained to them that Tom Robinson was shot dead attempting to escape from Enfield Prison Farm, and he was currently on his way to tell Helen Robinson that Tom passed away. Dill told Scout that a group of black children were playing marbles when Atticus arrived and Calpurnia followed him through the front gate. One of Helen's children then went to fetch her, and Dill watched as Helen received the devastating news of her husband's death. Dill tells Scout,
"...she [Helen] just fell down in the dirt. Just fell down in the dirt, like a giant with a big foot just came along and stepped on her. Just ump—...Like you’d step on an ant" (Lee, 244).
Atticus then helped Helen to her feet and walked her inside, where they remained for an extended period of time before Atticus drove Jem and Dill home.
The two boys had just returned from Barker's Eddy where Jem had completed his objective of teaching Dill to swim before he had to return home to Mississippi. They were back on the Meridian highway with little prospect of catching a ride home so late in the afternoon when the two boys saw Atticus approaching, but he failed to see them until they flagged him down. At first, Atticus told the boys they would need to continue their walk home, but
... Jem protested, then pleaded, and Atticus said, "All right, you can come with us if you stay in the car." (Chapter 25)
Atticus and Calpurnia were on their way to the home of Tom Robinson, where he was prepared to deliver the news to Tom's wife of his death. Dill told Scout that when Atticus spoke with Tom's wife, Helen, he never even had to tell her what had happened.
"... she just fell down in the dirt... Like you'd step on an ant." (Chapter 25)