The Grapes Of Wrath (1940)

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.

Tom Joad returns to his home after a jail sentence to find his family kicked out of their farm due to forecloseure. He catches up with them on his Uncles farm, and joins them the next day as they head for California and a new life... Hopefully. Based on the John Steinbeck novel.