Sammy Starling is a former gangster who has requested some special help from DCI Brock. It seems that Starling's wife has been abducted. His request is special because he was responsible 10 years earlier for uncovering corrupt police with one of the police, DI Marty Keller serving a 10 year prison sentence. Brock was the lead officer in the case back then and Starling believes that Brock is the only policeman who would agree to help him given his past.

When the ransom demand comes it comes in an unusual form, one that's got everyone scratching their heads. Instead of demanding money, Starling is ordered to buy a particularly valuable stamp and envelope at an upcoming auction and then deliver it to them. Although unorthodox, Brock and his team set up to cover the exchange, but things don't go as smoothly as hoped.

In fact, the fallout from the botched exchange results in the removal of Kolla from Brock's team, from which she is transferred to the Fraud Squad - a demotion in her view. Brock, on the other hand is suspended pending an inquiry that sees him facing charges of corruption over the way he handled the case. From here things take a sudden and dramatic turn as the case goes from a kidnapping / murder case to a forgery / fraud one. Kathy still can't come to terms with the suspicions surrounding Brock and suspects that there is a lot more going on than she is being made privy to.

Through some thorough investigation, Kathy begins to find out a few startling facts about Sammy Starling and the relationship he had with his wife. Suddenly, a crack begins to appear in the whole kidnapping scenario for her to slip a couple of inquiring fingers into. What she uncovers is a complex web of deception that dates back over 10 years.

A complete change comes over the pace of the story after the opening few chapters. It starts with a slow build up early on where we are given the kidnapping scenario mixed with a thorough lesson in philately paying particular attention to the history of stamps featuring the Chalon Head pose. But then, after the attempted ransom payoff we are thrust into overdrive as allegations are cast around, murders begin with alarming frequency and Kathy is compelled to push harder than she ever has done in the past.

With quite a lot happening over a short period of time, The Chalon Heads is a plot-driven story that grows in complexity, moving rapidly from a straightforward extortion to a more convoluted conspiracy. Barry Maitland has been developing his principal characters throughout the series so doesn't appeared to have seen the need to go into too much detail here. This is a little disappointing because Kathy Kolla was just starting to blossom as an individual rather than simply as a detective during All My Enemies. Here, she is cast once again simply as a detective with no outside life to speak of. I found that aspect to be just a little too bland in the context of the series so far. We are given a limited insight into Brock's past through his earlier involvement with Sammy Starling, but any detail about him is confined to his professional life rather than personal. He remains a very enigmatic character.

As a police procedural, this is a well-conceived and presented mystery that develops nicely into a tangled tale of deceit that heads for an unexpected ending. Maitland manages to keep the story fresh and interesting providing moments of intrigue mixed with complete shocks thanks to some deft shifts in direction (and misdirection). In Kolla he has created a tenacious and insightful investigator through whom he lays each step of the case out in a logical, plausible manner.

The Chalon Heads continues a very enjoyable police procedural series that makes good use of outside interests (in this case the breathtaking world of philately) while giving the reader an interesting mystery to solve.