The first of two books. It ends on a note that combines accomplishment with a bit of cliff-hanger.
It starts with Slate in a prison looking for a prisoner to take out. And smelling rosemary. She smells rosemary whenever she ought to be paying attention to something. Which is how she is led to a cell the warden doesn't want her to see. And chooses a paladin, incarcerated because he, demonically possessed, killed eight nuns and two guards.
She chooses him. She already has an assassin in her company, and she's a forger herself. The Dowager is sending them off on a suicide mission: to find out the secrets of the Clockwork Boys, the monstrous attackers who are winning a war with them, and what happened to the last company she sent.
This involves a coded book, fear of open spaces, a lightning strike, a old doe of the rune (a deer-like species of humanoids), gibbering in demonic tongues, a magical tattoo, and more.