Across the slow and weary days between Christmas and New Year, DI Cunningham's team try to make sense of a curious case of theft from an out-of-the-way valeting firm. Curious, because whilst they have been investigating a series of thefts of high-end sports cars - apparently the result of the hacking of data from a niche insurance company - this latest case simply does not fit the pattern. First, because of the - so far, unique - use of coercion: abducting the valeting firm's key holder. Second, because so many cars were taken - five. Third, because there were actually that many cars left over the holiday period - who could have known that would be so? Last, because the insurance company link does not actually connect to two of the cars. Then, no sooner has the New Year dawned than matters take a darker turn. Within hours of each other: peace falls apart on the borough's most depressed housing estate - with violence seemingly directed against one of the most prominent drug dealers; while a suspect in the car thefts is found murdered. Could there be a connection? In this long-awaited follow-up to The Chislehurst Murders, we see Francis Szeben's characters develop as the case unfolds. As with his highly acclaimed debut, the dialogue and narrative Szeben weaves places us right inside the police investigation. We are with them collecting and collating evidence, trying out theories, chasing down new leads, interviewing witnesses and suspects. The effort holds our attention as we turn each page, unable to put the story down. And central to the book is, of course, Martha Cunningham. Newly promoted to DI - the first of the Metropolitan Police's fast-tracked graduate recruits - we understand the slight angst she feels being used as something of a poster girl for the Commissioner's obsession with 'modernisation'. A rallying cry which feels more like a PR exercise for politicians than anything meaningful for those actually in the Force. And so, we are ever-so slightly proud of the way she seems to be easing into her role. Playing a part in the Yard's attempt to link various forms of smuggling when invited, but happiest leading her little team through its caseload. We see her growing up - learning to accept that she is no longer just one of the crowd. Yes, she's clever, posh, pretty and just a little full of herself at times - but she's also committed, funny when she chooses to be, insightful, loyal and liked. Liked and protected enough to find her team pulling her together at a moment when her confidence fails - a moment when she cannot help but think those dark turns in the case are somehow her fault. And those turns in the case are all part of the kind of detective fiction Francis Szeben is developing. The central murder investigation is - in itself - complete. But it is not self-contained. Rather, it links back to a thread in The Chislehurst Murders and forward into the next Cunningham File: The Chislehurst Avengers. Why? Because that is the real nature of policing. A detective's work is never so neatly packaged as a book: it does not start on page 1 and tiptoe to a neatly-drawn end. Rather, it twists and connects - meaning, what a good detective needs more than anything else is a way of valuing all information, not just that which seems relevant to the case immediately in hand. So, at the end of this book there is a small slice of the next one, just to keep us hanging on The Chislehurst Avengers will be published late in 2015.