Sally Lockhart has used her head for numbers to start up a consulting firm where she gives people financial advice. When an elderly teacher she’s advised loses all her savings after putting all her money into a shipping company Sally told her was a sound investment, Sally is determined to find out what happened. She is reluctant to ask her friend Frederick Garland for help, even though he now mainly works as a private investigator, as Fred would like nothing more than to marry her, and Sally’s really not sure she wants to give up her independence and business and become a wife.
Fred and Jim, a former street kid, who now works backstage at a theatre, and also assists Fred in his investigations, have a case involving a magician wanting protection from some very sinister underworld thugs, and as they start investigating, it turns out that the case of the threatened conjurer is closely connected to Sally’s investigation into the failing shipping company, and the formidable and sinister Swedish tycoon Carl Bellman seems to be the very dangerous mastermind behind all of it. He wants to marry a young and innocent noblewoman, and seems capable of using any means to rid himself of anyone who might get in his way.