I can always count on this series to be enjoyable. I was in a bit of a book funk and grabbed this off the shelf. Everytime I return to the world of Peter, Nightingale, and the rivers, it's like seeing a bunch of old friends. This was especially true considering that many of the normal characters were missing from the previous story. 

If you've gotten this far in the Rivers of London series, you know the drill. Peter is called upon to investigate a crime, there's some magic involved, the mystery deepens, and the "normal" police are both exasperated and thankful for the help of the Folly. I thought this mystery was good, and it was an added bonus that it moved the major series villain story along as well. Overall, a great addition to the series. ⭐⭐⭐⭐1/4