You've probably come across the statement in reviews of crime fiction that a book with a strong or unique setting is one where the location has become almost a character in the story. It's been said so often, though, that this pronouncement is somewhat of a critical cliche. Nevertheless, meet Rockton, arguably a major – if not the central – character in Kelley Armstrong's new mystery, City of the Lost (five more in the series are available as ebooks).

Armstrong, a Canadian, is best known as an author of fantasy fiction but like her American counterpart Charlaine Harris, as well as being an accomplished writer of mysteries, she is also a bit of a genre blender.

City of the Lost introduces us to Casey Duncan, who leaves her life and her job as a police detective in the city to take up residence in Rockton, a secret rural community where people go when they want to disappear. Casey is one of Armstrong's more appealing tough-yet-vulnerable female protagonists, and it's entertaining to speculate on the outcome of the romantic triangle which forms between her, Rockton's gruff Sheriff Dalton, and the buff Deputy Anders (but don't discount Casey's ex-boyfriend, who took a bullet for her, entering the competition later). Armstrong has always been adept at keeping us guessing, as she also does here, about the identity of the serial killer who is picking off Rocktonians in an inventively gruesome way.

It's Rockton itself, though, that keeps us turning the pages. Armstrong has fun playing with genre tropes in City of the Lost, and she doesn't limit herself to the paranormal or to crime. We're in Zane Grey territory here: Casey is the rogue gunslinger who rides into town to clean it up, a town with horse troughs, dirt streets and a bar manager who is also the madam of the local bordello. Currently there's a trend for fantasy writers to set their stories in hidden-away places: Charlaine Harris has taken us to Midnight, Texas, with Rachel Caine we've visited Morganville, and Armstrong has Cainsville, all creepy little hamlets where things go grrr! aargh! in the night on a regular basis.

Rockton, however, may well be the scariest place of all. Casey isn't fighting blood-sucking vampires in her new home, but she's made an enemy of an emotional vampire who remains unvanquished by the end of the book, a monster who will require something more than a mere stake through the heart to destroy.