Alex lives with her uncle in the flat above their doorknob shop. She meets her new teacher, Mr. Underwood, a descendant of a famous pirate, and soon three vicious men turn up in town, looking for a map to a fabled family treasure.

Cora, Nellie, and Michiko, teenaged assistants to three powerful men in Edwardian London, meet by chance at a ball that ends with the discovery of a murdered man, leading the three to work together to solve this and related crimes without drawing undue attention to themselves.