Ben Aaronovitch’s The Hanging Tree is the sixth book in the Rivers of London series and follows on from Foxglove Summer, Broken Homes, Whispers Under Ground, Moon Over Soho and the original Rivers of London. There are also a few nods to his graphic novel Body Work that is set before the events in this book, but it’s not crucial that you read it. There will be spoilers below…

After the fun and games in Herefordshire Peter Grant returns to London, but it’s not long before he is back in trouble after he gets a call about a young woman dying of a drugs overdose at a party in a swanky apartment near Hyde Park. He normally wouldn’t get involved in such police work but he is asked to join the investigation after it is discovered that Olivia the daughter of Cecilia Tyburn Thames aka Lady Ty, the goddess of the River Tyburn and the older sister of Peter’s equally magical girlfriend Beverly Brook, was at the party. It also becomes apparent that the dead girl, Christina Chorley, had brain damage caused by excessive use of magic.

Lady Ty, who once saved Grant from being crushed to death underground, wants her daughter Olivia kept out of trouble. Grant is given the awkward role of trying to help the investigation but also keep the powerful Lady Ty from doing anything illegal to help her daughter. Grant is partnered up with Muslim policewoman Sahra Guleed, a feisty young officer who knows nothing about magic but is keen to help with the investigation.

To add a further layer of complexity to the investigation it transpires that a hunt is on for a long-lost manuscript written by founding father Isaac Newton. His lost Third Principia was stolen by master criminal Jonathan Wild in the 1700s, and deals with alchemy and maybe even how to attain eternal life through magical healing techniques. Among those searching for the manuscript are the magic-wielding Lady Helena Linden-Limmer and her daughter; a team of tooled-up American wizards known as the Virginia Gentlemen who have links to the CIA; and Grant’s nemesis The Faceless Man along with Grant’s old flame and renegade copper Leslie May, who appears to have had her melted face fixed by some dark magic.

The titular Hanging Tree refers to the Tyburn tree around which the Chestnut Tree Pub is built. The tree was used to hang criminals and is said to be where Jonathan Wild met his end. The pub is now a meeting place for the magical beings of London and not really a place Grant should be visiting unannounced. However, he needs to investigate some details pertaining to the identities of those teenagers at the party and so pays it a visit. It’s there where he bumps into the shady character of Reynard ‘the Fox’ Fossman who might have got hold of the Third Principia and probably has a load of fake Rolexes sewn into the lining of his jacket.

The plot twists and turns like a Thames tributary until Grant finally, at long last, uncovers the identity of The Faceless Man as the nationalistic and vengeful Martin Chorley father of the deceased Christina. Grant, Guleed and Grant’s magical boss Nightingale, face off against Chorley in an explosive showdown back where the book started in the posh apartment building.

Unfortunately, because we are stuck following Grant’s movements, Nightingale’s epic magical battle with Chorley is unseen and happens in parallel with a rather dull run in with the already depleted Virginia Gentlemen followed by another fight with Leslie. Chorley set a lot of nasty traps for Nightingale, but lacked combat experience compared to Nightingale who fought Nazi wizards in WWII, and was therefore beaten down into seeking an escape rather than being captured by the police.   

Chorley and Leslie do indeed escape despite Reynard Fossman and Lady Helena’s involvement in a subsequent battle in the apartment block’s car park which initially appears to see Chorley killed in a collision with Fossman’s Tesla. The Third Principia is taken from the car’s boot by Lady Helena and Nightingale seems okay with that. The MacGuffin has served its purpose it seems.   

The Hanging Tree was a lot of fun and an easy read like all Aaronovitch’s novels. I particularly enjoyed the scene where Chorley needles Grant over his unexpected interest in history, since yet again Grant’s interests and pop culture references seem more an extension of Aaronovitch’s interests and reference points than you’d expect from the character. The references to Doctor Who and steampunk are also clearly coming from the writer not the character and this is the one weakness with the Rivers of London series that for me lessens its appeal compared to the work of similar writers who mix a magical world with contemporary life such as Neil Gaiman.