The Hope Diamond Mystery (1921)

Synopsis
A typical blood-and-thunder melodrama, this independently produced serial by Kosmik Films starred actor/stunt man Harry Carter as master thief Sidney Atherton, a man of many disguises. Blonde Grace Darmond played the imperiled heroine and other roles were taken by George Chesebro, Boris Karloff (as a henchman named Dakor), Carmen Phillips, and 1923 WAMPAS Baby Star Ethel Shannon. Produced by Poverty Row's George Kleine, the serial was written by veterans Charles Goddard and John B. Clymer. ~ Hans J. Wollstein, All Movie Guide