A 15-chapter Western serial. The serial involves the mystery of the murder of William Stillman (Wells) and the finding of the heir to his fortune. Silent Joe (Farnum) arrives in an effort to discover the murderer and prove that he is the true heir. He and the heroine Lou (Anderson) have their adventures in the mountainous terrain with its "vanishing trails." They are aided by The Shadow (Orlamond), a demented scientist with his trained dog, and several remarkable, death-dealing inventions.
After being unfaithful to "The Stranger", who committed a murder on her account, Cherry Millard, known as "The Siren", leaves to work in a dance hall in the Western town of Nugget. When Burt Hall arrives in town to deliver a will to the heirs of Bruce McClade, he is captivated by Cherry, who learns of Burt's mission. Discovering that the will dictates that Dr. Langdon, a friend of the family, is to receive $25,000, Cherry decides to impersonate Langdon's daughter Rose and thus gain possession of the money. In the meantime, The Stranger, who has been freed from jail, returns, recognizes Cherry as The Siren and kills her. This frees Burt from her evil spell, and The Stranger, now insane, follows The Siren's spirit into the desert.
A new town doctor arrives at the same time as local Indians needprotection from troublemaking looters.
Billy Milford, Harvard graduate, goes west to seek his fortune. In Addertown he secures a position as stationmaster of the L. & R. Railroad, but is forced out because of his drinking habits. He accidentally meets Gunhild, an emigrant Norwegian girl, as she arrives in Addertown to take up her home with Jan Hagsberg, the town's saloonkeeper. Seeking revenge on the railroad, Milford joins Jim Dorsey in a scheme to hold up the road's paymaster on his way to pay the employees of the company's mine.
Calvin Drake employs a group of low-lifes to drive away land owners along the path of a new railroad; Red Ryder opposes this strategy.
One of a multitude of short Westerns directed by D.W. Griffith in the early days of film has the distinction of being the screen debut of Western star Harry Carey in a minor role.
While out West, prospector Harry Webb makes enemies of a con artist, Mark Brenton and the con's crooked lawyer, Frank Beekman. Jack goes to the city and meets singer Janice Williams in a cabaret. They become engaged, but Brenton also has designs on her. He tricks her into going to a room to meet with him, and Webb, hearing of the scheme, follows. What he finds when he gets there is Brenton on the floor, dead, and Janice holding a gun.
Tom King Jr. seeks to discover who murdered his father, a Texas Ranger; the trail leads to a network of Axis spies.
Set in the Northwoods of Canada, Tom Mix stars as Donald MacTavish, the newly appointed head commissioner of the Hudson's Bay Company. This promotion infuriates MacTavish's rival Angus Fitzpatrick (Frank Clark) who wanted the job. Angus Fitzpatrick takes his anger and resentment out on MacTavish then sets out to get MacTavish fired.
In 1865, Captain Mark Smith of the Confederate Army leads a band of deserters to conquer Texas and rule it as a dictator. In one of his first actions, he captures and assumes the identity of Texas' new Finance Commissioner, Colonel Marcus Jeffries, after having the real man murdered. When a contingent of Texas Rangers enters the territory, Snead, one of Smith's men, leads them into an ambush by Smith's "troopers". The Rangers are apparently wiped out, although one injured survivor is left. The survivor, nursed back to health by Tonto, swears to avenge the massacre and defeat "Colonel Jeffries" and his men.