It’s pretty much impossible, these days, to chuck a stone in a decent-sized library without hitting a few fantasy books that are also mysteries or police procedurals, and since I’m a definite fan of all those things I rather like this trend.
It has to be done right, though, and done thoroughly enough—nobody ever talks about the Harry Potter books as fantasy mysteries, even though most of them follow that plot structure. This, on the other hand, is mostly mystery, with a hefty dab of mythology, and the fantasy elements are very well integrated with both.
It’s set in pre-Columbian America, in Tenochtitlan; the detective is Acatl, High Priest for the Dead, called in when someone is murdered by magic… and his own estranged brother looks like the obvious suspect. It’s not all paint-by-numbers plotting, however, and it gives a very similar sense of a detective out of his depth amidst politics, but determined to do the right thing, as Lindsey Davis’s Falco books or Liz Williams’ Detective Inspector Chen books (which de Bodard namechecks as an influence in her afterword, at that).
The worldbuilding is solid and consistent, and there’s a reassuringly sizeable bibliography at the back, which is always a good sign. A few things threw me (like the reference to drinking chocolate from a “clay glass”), but those are strictly minor issues. Overall, definitely recommended.