Synopsis by Hans J. Wollstein
Borrowing heavily from Robert Louis Stevenson, this Vitagraph serial released in 15 chapters starred Joe Ryan as Dr. De Brutel, a scientist/investigator infected with a mysterious disease that preys on his faculties. Periodically turning into a superhuman, Dr. De Brutel invents a "double x-ray " device that allows him to pass through solid matters, become invisible, and defy gravity. A respected citizen in his normal state, when under influence of the disease, the good doctor becomes the leader of a gang known as the Black Circle, an organization without moral scruples. The remaining 14 chapters depict an epic struggle between good and evil, with good, naturally, emerging the winner in the final chapter, "The Lifting Fog." Hidden Dangers was successful enough for Vitagraph to star former Tom Mix associate Joe Ryan in The Purple Riders but the serial did even more for leading lady Jean Paige, who was not only elevated to stardom but also married the company's co-founder, Albert E. Smith.