This exciting biography chronicles the life of the man who invented the M-1 carbine rifle, a gun that changed the ways in which wars were fought. The tale begins as inventor Marsh Williams serves a 30-year sentence for supposedly killing a revenuer during a raid in a brutal North Carolina prison farm. There he secretly occupies himself by building a new kind of gun. He doesn't plan to use it to escape. The warden finds out about William's illicit activity and takes the prototype. Williams then begs the warden to return it because he believes the weapon can help the boys fighting WW II overseas. When the warden sees that Williams is sincere, he allows him to finish the weapon.