Blackmail (1939)

John Ingram of Oklahoma has a loving family, loves his work fighting oil fires, and is good at it. But 9 years ago, under another name he escaped from a Southern chain gang. Enter William Ramey, a friend from John's past, who gradually works up to a blackmail attempt under a promise to get Ingram cleared...but instead has him sent back to the old chain gang. Though determined to tough it out this time, circumstances compel Ingram to attempt another escape.