John Mannering (aka 'The Baron') is secretly called to the house of William Blane by his young secretary Judy Darrow. He doesn't really know what to expect, only that a frightened girl had urgently summoned him in a midnight telephone call. Upon arrival, Blane is found to be dead and the girl is very nearly so. That, however, is not the beginning of an investigation, as 'The Baron' is now himself in danger. There is also betrayal and an angry and suspicious detective to deal with.