The rains do not let up for days. The Wainwrights are afraid that the boxcars will flood, and want to leave. Al says that he’ll go with the Wainwrights if the families split up. On the third day of rain, Rosasharn goes into labor. The Joads have no option other than to stay.
Things appear to be at their worst. Rosasharn’s pregnancy traps the Joads in dire circumstances, and, worse yet, Al’s choice to stay with the Wainwrights will divide the family.
Pa gets the rest of the men from the boxcars to help build a dam to protect the boxcars. They seem reluctant to stay, but they understand the Joads’ predicament and work tirelessly to build a barrier. The embankment they construct is torn apart by an uprooted tree. The current reaches the cars, and the Joads’ engine is flooded.
The men from nearby families risk their families’ safety in order to help the Joads. However, while their collaboration lets them overcome human cruelty, their joint effort still cannot overcome the elements.
When Pa returns from the failed effort to build the dam, Mrs. Wainwright tells him that Rosasharn’s baby was stillborn. Pa agonizes to Ma about his responsibility for the failed dam, but Ma tells him not to blame himself.
Once again, the Joads are powerless before nature—this time, disaster comes as a stillbirth. Although he has no control over his failure, Pa is wracked with guilt.
The baby is placed in an apple box, and Uncle John sends it down the current, hoping that it will “go down an’ tell ‘em. Go down in the street an’ rot an’ tell ‘em that way.” The baby is only able to tell its story by becoming a spectacle, and Uncle John hopes that it will arrive in town and convey the story of the migrants’ suffering.
Pa uses the family’s last bit of money to buy potatoes for dinner. After days of intermittent rain, Ma decides to move the family somewhere safer. Al elects to stay with the Wainwrights, and Ma promises to return to him.
Even at their most destitute, the Joads persevere. Ma’s instinct is to keep moving, always hopeful that things will be better elsewhere.
After the family marches down the highway, they come across a barn on a hill. Inside the barn, the family finds a father and a son. The father is starving to death and cannot keep solid food down. The boy begs for milk or soup to give his father. Ma and Rosasharn exchange a wordless glance, and Rosasharn says “Yes.” The family leaves the barn, and Rosasharn breastfeeds the starving man.
Rosasharn’s breastfeeding of the old man is the book’s ultimate act of altruism. On the most basic level, the act illustrates the profundity of the Okies’ desperation and need. The breastfeeding also shows that life and generosity can still come out of the tragedy that has befallen Rosasharn. And in the way that the act references the pieta—Mary's giving comfort to Christ—it suggests, like the grass growing after the storm—that the desperate circumstances that the Joads and the Okies must face will in the end produce a triumphant revolution of human spirit.