This book was, overall, disappointing. I said in my review of The Conductors that “the mystery was engaging, the magic interesting, and the characters great.” The sequel? The mystery was disjointed and poorly revealed. The magic wasn’t well used, and was explained either too much or too little. And Hetty and Benjy, who had humanzing flaws in book 1, felt like over-competent Mary Sues.
The central mystery of the book wasn’t well-handled. I was never clear on what, exactly, they were investigating, and parts of the dramatic tension felt extremely contrived. A non-spoiler example: a character was killed off-screen before the book began. Hetty & Benjy concluded it was the work of a White fire company, of the “very nice, flammable place you have here. Be a shame if anything happened to it. Care to make a donation to the Firemen’s Ball?” variety. They both had a gut feeling there was more to it, but they called it “case closed” and were annoyed at a mutual friend of theirs’ and the deceased who pressed them to keep digging. Fine for a world-weary, jaded cop three days from retirement. Totally out of character for Hetty or Benjy, from this book or the previous one. There are other examples of the same thing: Hetty and Benjy acting out of character for no reason I could see other than to raise the dramatic tension. A character holding the idiot ball always makes for annoying reading.
The villain is a former slave who worked for bounty hunters chasing runaways in the days before the Civil War. Hetty and Benjy had some run-ins with him, and he particularly has it in for Hetty. We’re often told how vicious he is (emphasis on “told”). There is no actual menace from him; we readers are just assured that it is there.
As far as the magical elements: something Brandon Sanderson articulated very well a number of years ago was the direct relationship between how frequently magic is used and how thoroughly it needs to be explained. It’s fine for Kaladin to use Stormlight all the time, because we readers understand what it can and cannot do and Sanderson keeps within those limits. On the other end of the spectrum, the magic of ASOIAF is left mysterious; if Melisandre or Thoros of Myr were to bust out with a Magic Missile for 1d4+1 damage (plus an extra missile per two caster levels) it … wouldn't work. The magic in this book falls right into this trap: it's used all the time, for purposes both fantastic and mundane, but I have no real sense of what the limits are on what it can and cannot do. It's a recipe for frequent deus ex machina.
Last point I want to touch on is Hetty and Benjy themselves, whom I called hypercompetent earlier. Benjy, for example, is a very skilled blacksmith; he is good with magic (he has some weaknesses there, which match very tidily to Hetty's strengths); he can play the piano beautifully; he is a voracious reader; he solves complex mathematical puzzles for fun; he has a powerful command of the stage as an actor; he is a champion boxer; he can pilot a hot air balloon. Hetty is similarly multitalented. Bluntly, it feels like there isn't anything they could fail at if they chose to try to do it. (As I write this, I'm realizing that this and the stuff I said about magic earlier probably explains the sources of drama feeling so contrived.)
Overall a disappointing read for me. I probably won't pick up Nicole Glover again without some solid reviews convincing me it's worth it.