James Lockhart sells banknotes. When four banks are robbed of $50,000 and two of the bank managers are killed shortly after Lockhart makes his deliveries, he becomes the obvious suspect.U.S. Marshal Rance Henson, "Marshal Doom", arrests Lockhart, as well as actress Marian Taylor, accusing her of being Lockhart's accomplice. Marian is a master of disguise, a pickpocket, and a contortionist, and helps them escape from Henson's custody so they can find out who the murderer is -- and clear their names.But the trail gets more dangerous with each mile they travel. Henson is a state-of-the-art 1880's lawman, burning up telegraph wires and the rails to stay one jump ahead. And he is falling for Marian, raising the stakes in a desperate game of cat-and-mouse.