The Mysterious Rider is a 1938 American Western film directed by Lesley Selander and starring Douglass Dumbrille, Sidney Toler, and Russell Hayden. Written by Maurice Geraghty based on the 1921 novel The Mysterious Rider by Zane Gray, the film is about a notorious outlaw who returns to the ranch he once owned and takes a job disguised as a ranch hand. Unrecognized by the ranch's current owner, he waits patiently for an opportunity to expose the men who murdered his partner twenty years ago, framed him for the crime, and then stole his ranch. The film was later released for television in the United States as Mark of the Avenger.

Plot

In the Arizona desert in the late 1800s, famed outlaw Pecos Bill (Douglass Dumbrille) and his sidekick Frosty Kilburn (Sidney Toler) hold up a stagecoach. During the raid, Bill takes money from a wealthy passenger and gives it to a poor woman passenger, then rides away. Having lived an outlaw life for the past twenty years, and still wanted for a murder he did not commit, Pecos Bill, whose real name is Ben Wade, decides to return to his home town disguised as a regular cowboy to see his now grown daughter.