A union leader enlists his girlfriend in a plot to get back at the railroad's evil management.

In rural Arkansas during the 1930s Depression, forthright sixteen-year-old farm girl Bertha Thompson watches as her father Jack plummets to his death while crop dusting. Having witnessed Jack's boss knowingly order her father to fly in a faulty plane, Bertha, hysterical with grief, attacks the callous man with the help of Jack's black mechanic, Von Morton, and Big Bill Shelly, a labor organizer who is working on a railroad gang nearby. Days later, rootless Bertha jumps onto a railroad boxcar to start a new life, carrying nothing but her clothes. Stopping at a rail yard, she is soon reunited with Bill, who is preaching to an angry crowd of workers, urging them to fight the railroad bosses and unionize Reader Rail Road. When violence erupts between the workers and the police, Bill whisks Bertha away to safety and finds a meal for her. Attracted by her equally rebellious nature, Bill gently seduces the virgin in a boxcar that night and leaves her some money before he disappears. Bertha uses the money to win at a hobo camp craps game against Rake Brown, a silent cardsharp. With Bertha's persistence, Rake finally utters something in a "Yankee" accent, immediately guaranteeing that he and Bertha are ousted from the camp, which is filled with Southerners. Realizing he cannot ply his trade without fitting in, Rake soon accepts Bertha's offer to teach him a Southern accent and idioms in trade for sharing the money gained from fleecing wealthy men in gambling parlors. Happy to have food and a place to stay, Bertha acquiesces to his sexual advances as well. One night, when a cheated customer, an attorney, pulls a gun on them, Bertha is forced to shoot the man in self-defense. Just outside, vengeful locals and the police are beating striking railroad workers and burning their camp, and Rake and Bertha jump on a boxcar with escaping workers. Spotting Bill, Bertha climbs into his arms, easily forsaking Rake, who realizes he is no match for Bill's charms. Soon after, when the police stop the car, Bertha escapes; however, Bill and Rake, along with workers, are taken to a jail. Bill finds Von there, but when he tries to speak with him, the attending officers call him a "nigger lover" and beat Bill mercilessly, inciting a riot between the prisoners and the bigoted police. Although Bill, Rake and Von survive the ensuing massacre against the prisoners, they are then sent to work on a chain gang as punishment. Days later, Bertha, posing as a woman in distress, distracts deputy sheriff Harvey Hall from his duty overseeing the railroad work, thus giving Bill the opportunity to knock him out with a shovel and escape with Rake, Von and Bertha in a stolen car. In the ensuing chase, Bill skillfully evades the pursuing police, including the sheriff, who drives off a cliff, but soon the car breaks down. After pushing the vehicle onto the tracks to cause the oncoming freight train to crash, the four rob the train of $12,000 and flee to a hideout, where they split the money. Days later, Rake reads the newspaper reports of their escapade out loud, including a description of Rake as a "coward" and Bertha as a "whore" implicated in the shooting of an attorney. As Bertha protests that the charges are false, Bill, Rake and Von realize that they have no choice but to continue a life of crime in order to survive. Still committed to the plight of the workers, Bill takes his $3,000 share to nearby union headquarters, but organizer Joe Cox refuses his money, insisting that his criminal reputation can only hurt the union now. Without the option of real work or unionizing, Bill stages a bank robbery in which he insists that in addition to handing over most of the bank's cash, the cashiers must add $10 to each worker's paycheck. They then rob the Reader Railroad, hoping to terrorize its owner, power-hungry H. Buckram Sartoris. Flustered but not intimidated, Sartoris immediately hires two sadistic railroad detectives, the McIvers, to capture Bill and the others. Days later, Bill, depressed that he is unable to return to honest work, suggests to Bertha that she leave him and their criminal life, but Bertha refuses out of love for Bill. Soon after, the gang robs Sartoris and his guests at a party the Sartoris is hosting. As the michievous Bertha takes their money and jewels, playfully draping them about her, Sartoris accuses Bill of being merely a common thief instead of a real Bolshevik. Buoyed by malice for Sartoris and confidence in their skills, the men later attempt to kidnap Sartoris on his own train, but the McIvers and several other thugs are waiting for them. While Bertha safely flees, Rake, feeling powerless and exhausted, bravely tries to defeat the McIvers and is killed. Von and Bill are subsequently sent to jail, where the police brutally beat Bill for his past union organizing efforts. Meanwhile, the now penniless Bertha is forced to work at a brothel, where she easily charms and satisfies her customers, but the work drains her of any hope. Then one night, Bertha recognizes the sound of Von's harmonica playing as she passes a black night club. Spotting Von on the stage, Bertha runs to embrace her friend, who tells her that, although Bill has recently escaped prison, he is quite ill. Von takes Bertha to the shack in which Bill is hiding, where the two reunite in bittersweet tears. As a weary and ill Bill warns her that his days are numbered, Sartoris' thugs arrive at the shack and beat both of them viciously, crucifying Bill by nailing his hands to a boxcar. When Von realizes what is happening, he reflexively grabs a shotgun and kills each of the assailants, including the McIvers, and releases Bertha's bound hands. As Bertha runs along the tracks while the boxcar carries Bill's lifeless body away, she begs the train not to take him from her.