During the Great Depression, a union leader and a young woman become criminals to exact revenge on the management of a railroad.

Based on "Sister of the Road," the fictionalized autobiography of radical and transient Bertha Thompson as written by physician Dr. Ben L. Reitman, 'Boxcar' Bertha Thompson, a woman labor organizer in Arkansas during the violence-filled Depression of the early '30's meets up with rabble-rousing union man 'Big' Bill Shelly and they team up to fight the corrupt railroad establishment and she is eventually sucked into a life of crime with him.—alfiehitchie

In the 1930's American south, Bertha Thompson decides to live the life of a transient after her crop duster father dies in a crash leaving her alone in the world. She grows up quickly from the experiences she has with various people she meets while riding the rails. Ultimately, she ends up traveling with three others: "Big" Bill Shelly, a laborer who now speaks on behalf of workers' rights and unions; Rake Brown, a gambler not averse to cheating and who carries a gun but is too scared to ever use it; and Von Morton, a harmonica playing black man who worked as her father's mechanic. Despite their different motivations in life, the four become fiercely loyal to each other, especially Bertha and Bill, both who consider the other to be the love of their life. Besides Rake's need to cheat to make a living, none of the four is predisposed to criminal behavior, but they end up living a life of crime out of circumstance, which included a card game gone wrong. Bill in particular feels uncomfortable with the criminal behavior in and of itself, except for the good he can do for the working class in the crimes. Even before their overtly criminal activities, they riled the police, who harassed them for riding the rails and for Bill's "Bolshevik" talk. But they also rile a railway owner named Sartoris and the sadistic McIver brothers, who work as henchmen for both the authorities and Sartoris, as Bill's pro-union/pro-striking diatribes are generally against the railroad. Hence, the battle between Sartoris/the McIvers and the foursome becomes a personal one on both sides.—Huggo

During the Great Depression, Bertha Thompson begins riding the rails and has a series of adventures, some lighthearted and others deadly serious. She gets involved with a less than honest gambler, Rake Brown, having to shoot her way out of a game when Rake is caught cheating. She also has a stint working in a bordello. She regularly crosses paths with union organizer Big Bill Shelley who is out to get a fair shake, by legal means or otherwise, for railway workers. They become lovers and take to robbing the payroll and when necessary, Bertha even breaks him out of jail. The railroad has its own enforcers however and Bill doesn't meet a just end however.—garykmcd