Second in The Ghosts. Spoilers ahead.
A simple mission to steal a merchant's ledger turns complicated when Caina discovers he burned in his bed -- without the bed or anything else having been burnt.
So Caina is set out with a skeptical Ghost named Ark, because another city has seen scores of these burnings. She poses as a countess with him as one of her servants. And they arrive to find much unrest, and that the dead include the city's entire circle of Ghosts.
It winds on, touching on the city's perpetual flames, accumulating lands for pasture sending peasants into the city as beggars, a history of piracy, much discussion of slavery, and more.