The October Man takes us across the Channel and introduces us to the German side of the magical world. And, as it turns out, the Germans have their own version of all this supernatural nonsense, complete with paperwork, police investigations and people who really should know better than to poke around with things they do not understand.

The protagonist this time is Tobias Winter, an investigator for the Abteilung KDA, the branch of the German Federal Criminal Police that is essentially the German equivalent of the Folly. He is sent to Trier to investigate a particularly unpleasant murder, where the victim has been found with some very strange injuries. Naturally, what initially looks like a fairly ordinary murder investigation turns out to involve magic, supernatural beings and the sort of local folklore that tends to make an already complicated case considerably more awkward.

What I particularly enjoyed about The October Man is that it manages to feel like Rivers of London without simply being Rivers of London. Tobias Winter is not Peter Grant with a German accent. He has his own personality, his own approach to magic and his own relationship with the supernatural. He is perhaps a little more experienced and self-assured than Peter was when we first met him, although that does not mean he has everything under control. Far from it.

There is also local Trier cop Vanessa Sommer, who finds herself working alongside Winter as the investigation develops. Their partnership provides plenty of opportunity for the sort of understated humour that works so well throughout the series. There is something wonderfully entertaining about watching an ordinary police officer gradually discover that the world is considerably stranger than she had previously been led to believe.

And then there is Trier itself. Moving the story away from London gives Aaronovitch the chance to explore a different corner of the magical world, while still retaining the mixture of police investigation and folklore that makes these books so much fun. The setting feels important without becoming a travel brochure, and the German mythology and supernatural elements give the story its own identity.

The police side of the story remains important too. There is a satisfying sense that Winter is actually investigating a crime rather than simply wandering around waiting for the next magical creature to appear. The supernatural works because it is embedded within a recognisable investigation, which makes the stranger moments feel all the more convincing. There is also plenty of the dry humour and slightly absurd bureaucracy that I have come to expect from this series.

At only novella length, The October Man is a much quicker read than the main Rivers of London novels, and I think that works in its favour. The story gets on with things without feeling rushed, and there is enough here to make Tobias and the German magical establishment feel like something I would happily return to.

The audiobook is particularly well served by Sam Peter Jackson, who deserves full credit for bringing Tobias and Vanessa to life with his narration. His performance gives the characters distinct voices and personalities, while maintaining the conversational feel that makes these stories so easy to settle into. He handles the humour particularly well, allowing the jokes to land without ever making them feel forced.

The October Man is a really enjoyable little detour into the wider Rivers of London universe. It introduces Tobias Winter and the Abteilung KDA while giving us a glimpse of how another country deals with the inconvenient fact that magic is real. It is familiar enough to feel like part of the same world, but different enough to stand comfortably on its own.

My only real complaint is that, like several of the shorter Rivers of London stories, it leaves me wanting more. Which, given that Tobias Winter is involved, is probably a sign that the Germans have got something right.

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