There is something rather satisfying about returning to a fictional world that already feels like it has been waiting for you. After enjoying Rivers of London, I was more than happy to follow Peter Grant back into the strange hidden corners of the capital, although this time things get a little darker, a little more personal and considerably more musical.

Moon Over Soho picks up Peter’s story as he continues his rather unusual apprenticeship as a policeman and trainee wizard. When a jazz musician dies after a gig and Peter discovers something decidedly supernatural about the corpse, he finds himself investigating a series of deaths connected to London’s jazz scene. Naturally, this being Peter Grant, things quickly become considerably more complicated than they first appear.

And that is one of the things I enjoy most about this series. Aaronovitch manages to make the increasingly bizarre seem almost routine.

There is still a huge amount of attention to detail in the police procedural side of the story. Peter isn’t simply wandering around London with a magic wand, looking for monsters to zap. He is still a police officer, and the investigation reflects that. There is legwork, evidence gathering, interviews, paperwork, forensic work and all the other practical details that come with trying to solve a crime.

It might sound like the sort of thing that would bog down an urban fantasy, but it actually gives the story its backbone.

The police procedural realism makes the fantastical elements considerably more effective because there is always something recognisably ordinary underneath them. Peter might be investigating a magical murder, but he still has to think about jurisdiction, evidence and what he can actually prove. When the supernatural turns up, it has to squeeze itself into the existing machinery of policing rather than simply replacing it.

That makes the magic feel surprisingly believable.

I particularly like that Peter doesn’t suddenly become an all-powerful wizard. He is still learning, still making mistakes and still trying to understand the rules. Magic has become another part of his job, albeit one that isn’t particularly easy to explain to the average member of the public. I can only imagine the paperwork involved in telling your sergeant that the suspect was a supernatural entity.

Then there is the Soho setting, which gives the book a very different flavour from its predecessor. The jazz scene provides a wonderfully atmospheric backdrop, and Aaronovitch makes good use of the history and culture surrounding it. Music isn’t simply decoration here. It is tied directly into the mystery, while Peter’s connection to the jazz world through his father gives the investigation a much more personal edge.

That family element is one of the things I particularly enjoyed. Peter’s relationship with his father gives us another side of the character, while the investigation gradually becomes about more than just another strange case. There is a sense that Peter is uncovering pieces of his own history at the same time as he is uncovering what happened to the victims.

And, of course, London remains one of the stars of the show.

I like the way Aaronovitch writes the city as somewhere with layers. There is the London that everyone knows, then there is the London of police stations, jazz clubs and back streets, and underneath all of that there is the ancient, magical London that has apparently been getting on with its business while the rest of us were busy paying the council tax.

The humour remains a big part of the appeal. Peter’s dry observations and slightly bemused attitude to the increasingly strange situations he encounters keep the story from becoming too solemn. Even when the subject matter gets darker, there is usually some wonderfully understated bit of humour lurking around the corner.

The characters also continue to develop nicely. Peter feels more confident than he did in the first book, but he is certainly not the finished article. Nightingale remains an intriguing presence, and the consequences of the previous book are allowed to have an impact rather than simply being forgotten because a new mystery has arrived. That gives the series a welcome sense of continuity.

But once again, I have to give full credit to Kobna Holdbrook-Smith for the audiobook.

He is absolutely superb.

There is something about his performance that makes Peter’s voice feel completely natural. The narration has the conversational quality that suits the character perfectly, but Holdbrook-Smith also manages to give the supporting cast distinct personalities without resorting to distracting caricatures. His timing is excellent, particularly with the humour, and he handles the shifts between police investigation, family drama and supernatural menace with real confidence.

Most importantly, he makes the whole thing feel alive.

You can hear the difference between Peter dealing with a colleague, talking to a family member, investigating a crime or suddenly finding himself confronted with something that really should not exist. Holdbrook-Smith gives each situation the right weight, while maintaining the dry, understated tone that makes the series so much fun.

Moon Over Soho is a very worthy follow-up to Rivers of London. It expands the world, develops Peter as both a policeman and apprentice wizard, digs deeper into his family history and introduces a mystery with its own distinctive atmosphere. The supernatural elements become stranger, but the police procedural grounding keeps everything nicely anchored.

I have very little to complain about. If anything, I simply wanted more of Nightingale, because the relationship between him and Peter remains one of the most entertaining aspects of the series. But that is hardly a serious criticism when there is so much else going on.

Once again, Aaronovitch has managed to create something that feels both familiar and completely bonkers. It is a police procedural, a supernatural mystery, a family story and a love letter to London’s jazz scene, all wrapped up in Peter Grant’s increasingly complicated life.

And with Kobna Holdbrook-Smith bringing it all to life, it is an absolute pleasure to listen to.

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