My Opinion on the book: A very good continuation, with the Faceless Man plot was paused (though next book is again an even number, so it'll should go with it). In addition, Nightingale moves somewhat into the background, because the investigations take place outside London, but he "in the home / Folly" remains. A nice change because Peter is placed more on their own in the investigation - but hopefully will not be the norm :)
I also like the fact that Beverly resumes a bigger role - it seemed a little too short and I am completely their mind in the last two volumes (I think it was in Broken Homes): Peter would have quiet times Report or visit can ...;)
It is also interesting that there is some more info about the events to Etter Mountain and also very roughly even to Molly's origin.
Something bad I find the end ... I found the decisions taken something illogical and last action something "irrational" ... well, without spoilers quite difficult to criticize ... Definitely me it not so well-liked, and a few more pages with a small explanation conversation would not hurt ...
Overall, however, a recommended book, if you like the Rivers-of-London-series - and as a side note: You can now (as of Nov 2014) Pre already tape number 6 - it says "Hanging Tree", delivery is but only November 2015 :(