A brilliant scientist, who has discovered the secret formula for a super-powered explosive, has been kidnapped and tortured to madness by foreign nationals. As the formula resides only in his mind, they kidnap a second person- a famous psychiatrist-who is their only hope in extracting it from the scientist's brain. Lamont Cranston, as the Shadow, and Margo Lane learn of the dastardly plot by a telepathic phone call from the psychiatrist and work against time and international waters to thwart the evil plot.