The story starts out by Tom Joad hitchhiking home. Once they arrive, they find Tom's family packing up and getting ready to go on a trip. Tom's father explains to him that the banks and large companies closed out all the small farmers, and now most of them are heading out to California where there is supposed to be work. When everyone was ready to leave Grampa Joad didn't want to go, so they had to drug him to get him into the car to go on their way. When they stop to rest on the first night of the journey, Grampa Joad has a stroke and dies immediately. They bury Grampa along the way to California in a blanket some migrants gave them. The migrants were the Wilson's, who car had broken down. The Joad family offered to help fix their car, and one it was fixed the two families began their trip together.
Once they reached California, Mrs. Wilson got really sick, so the Joad family gave the Wilson's some money and food and continued on their way.
During the whole trip out west, Granma Joad had been getting sicker and sicker, Ma Joad finally realizes that she's dying. They had to start a long drive through the desert one night, and while they were driving Granma dies early into the night. A guard stops them during their trip and Ma Joad explains to the guard that they need to get to a doctor because Granma is very sick. The guard let's them go, and Ma tells the family to drive on. Once they make it safely across the desert, Ma tells the family that Granma is dead, so they must bury her as a poor person because they don't have enough money for the funeral.