The Vanishing Legion

The Vanishing Legion is a 1931 American PreCode Mascot film serial directed by Ford Beebe and B. Reeves Eason.

Masked mystery villain, The Voice, is out to sabotage the Milesburg Oil Company. Happy Cardigan needs to successfully drill for oil before his contract with the Milesburg Oil Company expires or go broke. Jimmie Williams father, Jed Edward Hearn, has been framed for murder. Secretary Caroline Hall appears to have an ulterior motive. The mysterious Vanishing Legion is also on the scene. Jimmie and Cardigan team up, along with Jimmies horse Rex, to defeat The Voice and solve the mysteries surrounding Mileburg.

Source: Wikipedia