Tana French devised a plot construct so thrillingly extraordinary I was expecting a completely absorbing book. But it was sadly let down by an unnecessary lack of realism in the detail of police procedure and practice. Protagonists in detective fiction are often dysfunctional, but they are usually, eventually, good at what they do. For all the gloss the author attempts to apply, Cassie Maddox fails this basic test in every way.

Instead of apprehending the real perpetrator of a crime passionnelle, she covers up for him, forcing another character to claim responsibility before she shoots him. This after hiding key evidence, breaking her cover and blackmailing her handler. In all she destroys four lives (and is responsible for their home being burnt down). Yet somehow this risibly unprofessional detective gets a light slap on the wrist and, presumably, will go on to wreak further destruction in succeeding novels.

I understand the author's desire to maximise the tension within the narrative, but I could not suspend my disbelief sufficiently to enjoy much of the book. And that's sad, because Tana French writes extremely well and, as my opening sentence attests, is capable of jaw-dropping plot devices, three dimensional characters and stylish and enjoyable writing.