Ben Aaronovitch’s latest novel in the Peter Grant/Rivers of London series – The Hanging Tree – brings us back to London after Peter’s foray into the countryside in Foxglove Summer. The focus is on Mayfair this time as Peter investigates a drug-related death where one of the suspects is the daughter of Lady Tyburn, physical manifestation of one of London’s rivers and not one of Peter’s biggest fans. As the fateful events are gradually revealed and the implications uncovered, new players in the magical scene are introduced, some familiar faces reappear, and a bigger mystery might just be solved.