One evening, Ma Joad watches Winfield as he sleeps; he is writhing and he seems discolored. In the month that the Joads have been in Weedpatch, Tom has had only five days of work, and the rest of the men have had none. Ma worries because Rose of Sharon is close to delivering her baby. Despite these troubles, Ma reprimands the rest of the Joads for becoming discouraged. She tells them that in such circumstances they don't have the right, yet Pa fears that they will have to leave Weedpatch. When Tom mentions work in Marysville, Ma decides that they will go there, for despite the pleasant accommodations at Weedpatch the Joads have no substantial opportunities to make money.

Thus, the Joads plan to go north, where the cotton will soon be ready for harvest. Aware of Ma Joad's forceful role within the family, Pa remarks that women seem to be in control and that it may be time to get out a stick. Ma hears this, and tells him that she is doing her job as wife, but that he certainly isn't doing his job as husband. The younger family members also reflect on their relationships: Rose of Sharon complains that if Connie hadn't left the Joads would have had a house by now. Al parts ways with a blonde girl that he has been seeing; she rejects his promises that they will eventually get married. (He promises her that he'll return soon, but the girl does not believe him.) Pa remarks that he only notices that he stinks now that he takes regular baths. Before the Joads leave, Willie remarks that the deputies don't bother the residents of Weedpatch because the residents are united, and a union may be the solution to the laborers' troubles.

The car starts to break down as the Joads leave, since Al has let the battery run down, but he fixes the problem and the Joads continue on their way. Yet Al remains irritable. He says that he's going out on his own soon to start a family. On the road, the car gets a flat tire. While Tom fixes the tire, a businessman stops in his car and offers the family a job picking peaches forty miles north. The Joads reach the ranch at Pixley where they are to pick peaches for five cents a box; even the women and children can do the job. Ruthie and Winfield worry about settling down in the area and going to school in California, since they assume that everyone will regard them negatively and call them Okies.

At the nearby grocery store, which is owned by Hooper Ranch, Ma finds that the prices are much higher than they would be at the store in town. The sales clerk lends Ma ten cents for sugar. She tells him that only poor people are willing to help out. That night, Tom goes for a walk, but a deputy tells him to walk back to the cabin at the ranch. The deputy claims that if Tom is alone, the reds will get to him. While continuing on his walk, Tom finds Casy, who has been released from jail and is now with a group of men who are on strike. Casy claims that people who strive for justice always face opposition, citing Lincoln and Washington, as well as the martyrs of the French Revolution. Casy, Tom, and the rest of the strikers are confronted by the police. A short, heavy man with a white pick handle swings it at Casy, hitting him in the head. Tom fights with the man, and eventually wrenches the club from him and strikes him with it, killing him.

Tom immediately flees the scene, crawling through a stream to get back to the family's cabin. He cannot sleep that night, and in the morning tells Ma that he must hide. He tells her that he was spotted, and warns his family that they are breaking the strike: they are getting five cents a box only because of this and may get only half that amount once the strike is over. When Tom tells Ma that he is going to leave that night, she tells him that they aren't a family anymore. In her view, Al cares about nothing more than girls, Uncle John is only dragging along, Pa has lost his place as the head of the family, and the children are becoming unruly. Rose of Sharon then screams at Tom for murdering the man, since she thinks that his sin will doom her baby. In yet another blow to the Joads, after a day of work, Winfield becomes extremely sick from eating peaches. Uncle John tells Tom that when the police catch him, there will be a lynching. Tom insists that he must leave, but Ma insists that they leave as a family. The Joads make sure to hide Tom as they leave, taking the back roads to avoid detection by the police.