Synopsis by Hans J. Wollstein
Pearl White was back in this 20 chapter action serial from Pathé, this time playing Pearl Standish, a young girl fighting to retain a priceless violet diamond supposedly stolen by her father from an underground lost city. To regain possession of the diamond, Pearl is aided by Nicholas Knox (Earle Fox), a former adversary she has managed to win over to her side with her charming personality. The opposition, however, is rather powerful and includes both the High Priestess of the Sacred Order (Ruby Hoffman) and the debonair but deadly Richard Carlslake. The latter was played, to the hilt according to surviving reviews, by Warner Oland, the Swedish-born character actor who would eventually gain international fame as the clever Honolulu-based detective Charlie Chan. This early in his career, however, Oland was almost always cast as a heinous villain and would, in fact, return to menace poor Pearl in The Lightning Raider (1919).