A few minutes before he is killed by an unseen gunman using a split-butt rifle, in a saloon in Tumult, Wyoming, railway employee Harley Masters gives a secret map to Deputy Marshal Ed Garry. Garry is questioned about the murder by Master's niece Janet; her cousin Bill Masters; the town big-shot, Joel Benton and Doc Vinson. Garry meets Claire Benton when her brother and his henchman Eli Cressett question Garry about the map. Garry accuses Cressett of being one of the two wanted men he is seeking. Cressett, aided by Benton, escapes from jail. Garry and Janet find a split-butt rifle near where one of her hands was killed in a rustling raid. They take it to town and Garry telegraphs the Winchester Arms Company and asks the name of the purchaser based on their serial number records. Cressett meets with Bill Masters, the real leader of the gang, and is offered more money if he will kill Benton. He agrees, but intends to double-cross Masters.