This is a steampunk tale with magic and logic (although the latter is really a form of anti-magic), set in an alternate history England. As promised in the other reviews, the conclusions of the main characters aren't spelled out to the reader, which is a pleasant change from many similar books and adds a little spark.
Emma ("I am not a lady") is a rather overpowered magic user, and appears to be highly placed. It seems that she could do anything she wished, including solving the plot that this novel is based around, with a click of her fingers. I feel that she tells me rather more about the author than I need to know. Clare (male, surname) is a poor copy of Sherlock Holmes; the abilities without the character. The other principal characters are rather flat - Ludo, the Italian assassin who switches accents at the drop of a hat, and the rather forgettable "Bavarian genius".
The world has a history, as do the main characters, none of which is fully spelled out. This is probably a good thing, as we are given enough to drive the main parts of the plot. The main annoyance was that the story is largely set in a London that corresponds very closely to our own, with similar, but different for absolutely no reason, place names; the setting is a steampunk Victorian era. The history of this world obviously diverged a long time ago (I would guess pre-Roman), in the "Age of Fire" before the "Age of Bronze", and yet we are expected to accept the setting. The changes to names (St Jemes Park, or Victrix for Victoria, etc) are unnecessary given that we accept the setting, and so manage to annoy.
Unless you enjoy this authors other works, one to skip. Extra star for world building and background; two each deducted for annoying spelling and flat characters.