The third book in the Kat trilogy. More magic and adventure in a semi-Regency setting.
Kat and her family are en route to her second sister's wedding, and even on the way, there is someone lurking about, a carriage accident, and a marquise -- a woman who married a French nobleman, and who is known to Kat's father.
And so to arrival, where Mrs. Carlyle still has not reconciled herself with the marriage, and the Order tells Kat there may be problems with her initiation, since the portals were stolen.
The tale involves secret passageways, discussions of gambling and drink, secret passageways, Kat's brother taking in a woman to dinner because of Kat's craftiness, a resentful son, smuggling, and threads from the prior two books being tied up -- among other things.