Tom learns his family is up at Uncle John’s – but not for long, as he too has been evicted. They are all surprised to see Tom out of jail, and he agrees to relocate with them in California where it is rumored that there is work, even if it means he must break his parole. Ma Joad worries prison may have changed her son. Tom greets his siblings and learns that his sister, Rosasharn, has married and is pregnant. Ruthie and Winfield spin wild stories of how he must have broken out of jail.

At the same time, Tom’s 16-year-old brother Al is buying the truck that will make the 2,000-mile trek. Hucksters try to sell him a wreck, but the mechanically inclined teen feels he’s made a good deal. The family isn’t quite so sure. Nonetheless, Granma and Grampa are thrilled by their prospects out west, while Ma laments the loss of the land and belongings that have meant so much to them.

The next day, Grampa is a little less exuberant, but the family loads him up into the truck along with their few remaining possessions and heads down the plenty road with Casy along for the ride. Though all remain optimistic, traveling along Route 66, Tom and the others experience their first disparaging remarks, now labeled as “Okies.”

As the Joads set up camp for the night, they meet other travelers who have handbills identical to Pa’s. One ragged man has already been to California and reports that there is no work left. In order to keep wages low, ranch owners print thousands of handbills when they only have a hundred jobs available. His entire family perished from famine. Pa remains confident that they will find work. Elsewhere, dangling their feet off a highway overpass, Connie and Rosasharn watch the passing traffic. Connie admires the Lincoln Zephyr, while Rosasharn dreams of a home for her new baby.

The next day the Joads soberly bury Grampa, who has died during the night. Casy says a few words in praise of the old man. The family then continues their journey down the road.

At a diner, a waitress chats with truckers. Pa and Ma enter with Ruthie and Winfield in tow, and she looks at them with contempt. They try to buy a loaf of bread for Granma (who is now sick) as they prepare to cross the Mojave Desert, but they only have a dime. At the urging of her husband, she gives them the loaf at a discount. Suddenly moved, she throws in two lollipops for the kids.

As they cross the dry Mojave, the men drive the truck while Connie makes amorous overtures to a reluctant Rosasharn. Ma rests with Granma. The old woman has died, but only Ma knows it. The next morning, after passing through an inspection station and reaching the beautiful Telachapi Valley, the awful truth is revealed. Ma had promised Granma she’d be buried in a green place.

At the Endicott Farm, the scene flashes back to 1849. California settler George Endicott plants his first plum tree. In the present time, growers inform the Joads that there’s no work there – the crop already has been picked. Another flash to 1924: George Endicott the grandson has become a successful businessman. Back in the present, the locals rally – with the influx of Okie laborers, their wages have been slashed. Meanwhile, Endicott iv enjoys the finer things in life. Nearby, Tom and Winfield watch as plums are burned – the farm grew too many, and to drive up the price, they destroy the excess, rather than give them to the hungry croppers.

The Joads continue on, settling in Hooverville, a squalid shanty town by the railroad tracks. A cropper woman tricks Ma out of a few potatoes by pretending a bag of leaves is a starving child. The family is disgusted by their new surroundings but have little choice at the moment. Al angrily reproaches his slow-witted brother Noah for being more of a burden than a help. He wants to break off on his own, but Ma takes charge, insisting the family stay together. Begging a dollar from Ma, Uncle John goes off on a bender. Connie regrets his leaving what little he had in Oklahoma and derides Rosasharn’s hopeless dreams of home and family. He storms off, never to return.

The next day a contractor and a deputy show up with more handbills offering work. Al is suspicious and Casy asks to see the contractor’s license, causing a stir. When the squatters refuse to go, the situation becomes agitated. The deputy tries to cuff Tom, but he escapes, and the ensuing bullet meant for him hits a nearby woman, killing her instantly. In the growing scuffle, the deputy is knocked unconscious and the contractor runs for safety. As the deputy comes to, Casy chooses to take the blame, as the Joads make a beeline for the truck. Rosasharn is distraught, for Connie hasn’t come back. Noah goes to the creek to fetch a bucket of water and instead submerges himself, never to return. Ma recalls simpler times.

Newly relocated at a government settlement camp, Ruthie and Winfield marvel at the flushing toilet, the first they have ever seen. Ma instructs them in the merits of modern plumbing and hygiene. The camp makes them feel like people again, though Ma is startled to discover she accidentally has gone into the men’s room. Inside the inner shower room, the Men’s Committee meets. Outside, the women gather as they wash clothes, instructing Ma on the rules of the camp.

Rosasharn is now very pregnant and despondent over Connie’s departure. Ma tries to comfort her with sage advice. Later, at the camp hoedown, the Joads joyfully take part in a square dance. Three vigilantes try to cause a disturbance, but the crowd, aware of their prearranged plan to create a riot, makes the expulsion of the intruders part of the dance. When two deputies arrive to break up what they think will be a fight, they leave disappointed. The local farm owners are obviously unhappy with the camp’s growing autonomy.

Pa shows everyone a new handbill with great enthusiasm, but the crowd responds dishearteningly. Nonetheless, they prepare to pack – as good as the camp may be, there is still no way to make money for food as long as they reside there.

At Hooper Ranch a strike is in progress, but the Joads and others are quickly ushered by the line, unaware they are scabs. As they pick the peaches, Tom questions what is happening beyond the fence, but is quickly silenced. Though thrilled to finally have some money, Ma soon discovers how inflated prices are at the local commissary. Other things – ladders, housing, showers – also prove to be expensive and the Joads are barely better off than they were before.

Later that night, Tom takes a closer look at what’s going on outside the fence. He discovers a group of men, one of which is Casy, who leads the strike over poor wages. Vigilantes soon arrive and bludgeon Casy to death. Tom wrestles the club from the attacker and is slashed on the face. He in turn bashes his assailant, killing him.

Now a marked man, Tom has gone into hiding and Ma smuggles him some food. He announces his plan to go off on his own and they share a tender moment. The remaining Joads find work picking cotton and shelter in a boxcar. Just as the rainy season begins, Rosasharn goes into labor, but delivers a stillborn child. Instead of burying him, Uncle John floats little dead Moses down the rising stream.

The raging river has now swallowed its banks and flooded the Joads out of their homestead. Only Ma, Pa, Ruthie, Winfield and a very weak Rosasharn remain and seek refuge inside a barn. There they find a boy and a starving, nearly dead man. Ma intuitively knows what Rosasharn must do, and ushers everyone else back outside. Rosasharn lowers her blouse and nourishes the man with her breast.