Delmar Spavinaw, an educated "half-breed," loves Evelyn Huntington, daughter of a racist judge. Evelyn's other suitor is Ross Kennion, a widower with one child, and owner of a vast tract of land which Spavinaw insists belongs to his Indian mother. Spavinaw seeks revenge when Judge Huntington decides to evict the squaw. Assisted by Juan Del Rey, a cattle rustler, Spavinaw steals the title to the land, wounds Kennion, stages a raid on the judge's cattle, and attempts to kidnap Kennion's son and Evelyn. The arrival of the sheriff forces him into flight across the border without his hostages. En route he meets Doll Pardeau, a school friend of Evelyn's, and together they ride for the Mexican border. Caught between a cattle stampede and a sheriff's posse, the couple catch a passing freight train, leaving calamity behind as the train slowly passes.

When a couple of scammers hold young Alice Faulkner against her will to discover the whereabouts of letters whose dissemination could cause a scandal affecting the royal family, Sherlock Holmes decides to take over the case. (Considered lost, a copy was found in 2014, in the vaults of the Cinémathèque Française.)