This was my first encounter with Acatl and Aliette de Bodard, and it was an enjoyable meeting. May there be many more!
This novel is a fantasy/mystery based in 16th century Mexico; the Aztec empire, to be exact. Our detective is the High Priest of the Dead, which is a curiously less blood-thirsty priesthood than the rest of the (real) Aztec clergy were. The gods are real and take their parts in this story; the opening scene is a magical invocation where we aren't quite sure if the magic effects are real or imagined - but this is resolved shortly, coming down firmly on the side of magic as a possible murder scene is investigated.
Along the way we meet real characters with some depth who, presumably, have figured in previous Acatl short stories, as we move towards a resolution of the initial murder. The participants all have some depth to them: Acatl is a competent and perceptive investigator, although not peculiarly unsuited to be a high priest, and he has his flaws that are clear to the reader, although less so to him. It is rare to see such competent character handling in a genre novel, let alone a first one.
I wasn't entirely comfortable with Acatl as High Priest; there seemed to have been a lot of background unrevealed that would be required to explain his promotion, which may possibly be intended to come out in later stories. The transition from a form of locked room murder mystery into epic swords and sorcery fantasy was not entirely a happy one - the last several chapters were a big swirl of purple prose that jarred with the mystery format, although the relevant identities were all revealed satisfactorily as that genre demands.
Here's a tip for readers who find Aztec names troublesome: just look at the first syllable; the author has managed to keep them reasonably unique and pronounceable if you ignore the rest of the name. At least they are pronounceable using English conventions, unlike Gaelic names!