Molly Murphy can't seem to fit in anywhere. Not with the new immigrants pouring in from the Old World and certainly not with the society folk she envies from afar. After bungling a job as a lady's companion, Molly decides to become an assistant to the notorious private investigator, Paddy Riley. Unfortunately, Paddy's underworld dealings leave him deader than a doornail and Molly in possession of his detective agency. Using the tricks of the trade learned from her employer, Molly sets out to find the wily killer responsible for the death of Riley.