I've been evangelizing for this series since I first read Rivers of London (aka Midnight Riot). But after Foxglove Summer and now The Hanging Tree, I find my enthusiasm waning. And that breaks my heart.
It could be that it's been just long enough since I read the earlier books that, when this book references characters and events, I struggle to recall what happened when and who so-and-so is. The whole thing has become unwieldy; I almost need a cast of characters or a timeline or something. (That probably exists online somewhere...)
Can I even describe the plot here? It's kind of a mess. Starts with someone overdosing at a party, and Tyburn's daughter Olivia is implicated. But then things veer off in a variety of directions, with American magicians thrown in. And of course more with Lesley and the Faceless Man which, though progress is made, I'm sort of sick of this particular plot. The "we almost caught them!" thing is getting really, really old.
In any case, this one felt disjointed, what with the hinky plot going from one thing to the next like a pinball. And I noticed the typos became more frequent as I went along, which makes me wonder whether there was deadline pressure and they cut a copyediting/proofreading pass toward the end. (Having worked in publishing, I've known it to happen. And Foxglove Summer similarly felt rushed at the end.)
I still think this should be a television series. And I'll continue to read the books, at least for now. Maybe these are just a slump. Though I also acknowledge how much harder it is to hold something together the larger it becomes. The Peter Grant series is starting to be behemoth. Lots of characters, lots of rules for how the magical world works . . . Might be time to contract it a bit and get back to the really good stuff.