Magic develops further, and we get an entire new race below London. Still very witty, and I just cannot resist a “magic underground in London” story. At the same time, it’s a whodunnit, and the banter continues the strong suit of the series, while the plot (especially the overarching series plot) does well to stay in the background.
I'm currently behind on reviews, so don't be surprised if the recent reviews are a bit sparse.