Oklahoma in the thirties is a dustbowl and dispossessed farmers migrate westward to California. After terrible trials en route they become little more than slave labor. Among the throng are the Joads who refuse to knuckle under. An account of a depression-era family's migration to the greener pastures of California based on the novel by John Steinbeck. An Account Of A Depression-Era Family'S Migration To The Greener Pastures Of California Based On The Novel By John Steinbeck.