Book cover: Foxglove Summer - Ben Aaronovitch (blood smearing across a map of the English countryside)Reeling from recent betrayals, Peter Grant finds himself packed off to the Welsh borders to rule out magical interference in a child abduction case and take some time out in the country air to work through his tangled emotions. If only life were that simple.

I’ll admit to approaching Foxglove Summer with some trepidation: child abductions are touchy subjects, and I didn’t entirely trust Aaronovitch to handle one with care. I needn’t have worried. As observed in previous volumes, PC Grant has grown up and Aaronovitch is cautious in approaching his tricky subject matter (no repeats of the shocking baby incident in Rivers of London).

In fact, Foxglove Summer has unexpectedly ended up being a joint series-favourite for me (alongside Broken Homes). Not only do we see Peter out of his element and in reflective mode (the scene in which he confronts his feelings about Lesley is brilliant), but we get to find out more about Nightingale’s past as Peter pays a visit to another Folly alumnus, Hugh Oswald, and his mysterious grand-daughter Melissa.

I am always here for finding out more about Thomas ‘Tiger Tank’ Nightingale – it’s increasingly clear that he really is the Bond of his generation (his Jag and the Broken Homes cufflinks moment are no coincidence): far more powerful than he ought to be, loyal to a fault, and deeply damaged by his past. Ettersberg can and does get worse the more you hear about it. Throw in some Homer and I frankly got a bit weepy. Somebody give Nightingale a hug. I’ll take one, too.

…although it’s not like Peter has a lot of spare emotional capacity for processing any of this; before he can begin to come to terms with her choices, Lesley gets in touch. The careful cat and mouse game by text message had me yelling at the page (nothing complimentary) and – eventually – applauding in delight (well played, Peter. You adult you) – long before her bleak warning that the Faceless Man would eat them all for breakfast. I thought I was on tenterhooks to find out what happened next at the end of Broken Homes; I had no idea.

Somehow, all this well-engineered emotional tension provides a baseline for the main action, rather than becoming a distraction – as the core case proves unrelated to anything we’ve seen before and a puzzle in its own right. The countryside has its own rules, and I loved that we got to see additional dimensions to what we know about the supernatural. Aaronovitch teases us with aliens, fairies and unicorns, and his ideas about the rural demi monde are happily as vivid and satisfying as anything conjured in Lychford. I’m always worried when people tackle fairies and unicorns, because I have quite firm (and rather unVictorian) ideas about them; Aaronovitch goes with full-on blood-soaked terrifying, much to my delight.

As if this weren’t enough, we also get the return of Beverly Brook (because every supernatural investigator needs a female side-kick who can kick his ass) and the introduction of the entirely charming local plod Dominic, whose ideas about loyalty and commitment are as confused as Peter’s own.

While Foxglove Summer is arguably a diversion from the series meta-plot, I found myself fully-engrossed from start to finish and honestly delighted by its twists and turns. I am now more curious than ever about the nature and births of river god(desse)s and fae (just what is Melissa, anyway?) and OH GOOD GOLLY MISS MOLLY are there some surprises in store along the way.

****