The film follows the life of David Marshall Williams, who was a member of the Winchester team that invented the semi-automatic M1 Carbine used in World War II. Williams was found distilling illegal moonshine, and was held responsible for the death of a sheriff's deputy during a raid on his still. He was sentenced to thirty years' hard labor. He cycled through the prison system until a firm but compassionate warden, H.T. Peoples, allowed him to work in a prison tool shop. There, he invented the gas system for his famous rifle. Williams was released from prison in 1929 and worked with Winchester Firearms on development of the M1 Carbine.