The sequel to Mairelon the Magician. Spoilers for that ahead.
Kim finds London, magic lessons, the prospects of a Season, and Mairelon's aunt who is effectively her chaperon much more tedious than she expected when she agreed to become his war. Though when she hears noises in the night, and goes to investigate, she not only finds a burglar, but one who is using magic. Attempting to track down what he was interested in, in the library and elsewhere, leads to more complications. A friend of Kim's from her old days warns her of a danger. And Aunt Agatha's attempt to throw Kim into society and marry her off lead to Mairelon's jesting about her having a coming-out ball and Renee D'Auber's explaining that, actually, a formal Season would in many respects be the best thing for both of them.
And the story winds onward through intrigues, involving a Russian prince, a magician who drowned at sea, illusions other than climbing roses, a money-lender unaccustomed to the Quality when they are not looking for money, opera, the trick to why magic needs fancy languages, and a burglary at a hotel. Among other things.