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.
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.
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 mountaineer, who has been shot by a pursuing sheriff, is concealed by a mountain girl in her cabin. When the sheriff arrives, she gives him whiskey, while secretly removing the bullets from his gun.
Three Outlaws came across a stranded baby and must decide to save the child or escape from the law.
The life of Sam Houston, soldier, statesman, patriot and one of the founders of the Republic of Texas, is depicted.
Before dying, a man's friend asks him to do his best to keep the truth that he was a robber from his son.
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.
Out of the talk at the Sportsmen's Club arises a wager between the globe-trotter and his friend, who bets that he will not be able, within a fixed time, to find his way out of an isolated mountain location to which he will lead him.
Two road agents hold up the stagecoach and rob the passengers. In making their getaway, one of the road agents is shot by the stage driver. They stop at a lonely cabin, where a miner's widow lives with her little daughter, and ask for aid.