It's an old thriller standby - good cop gone rogue - but seldom has it been told with as much power as in this debut by Auckland ex-detective Nathan Blackwell.
That's a pseudonym by the way, needed because in a 10 year police career, which included investigating drugs, abuse and murder - some was conducted covertly.
Yes, Blackwell's police experience ensures it's a realistic insight into the workings of Auckland's Criminal Investigation Branch - there's even a glossary so you know your NIA's from your SOCO's - but it's Blackwell's no-bullshit prose and ripped-from-the-headlines storytelling, that sets this apart.
Ex-cops writing novels is nothing new of course - an ex-colleague of Blackwell's - Simon Wyatt - penned a good police procedural The Student Body last year - and again - the Force's loss is crime fiction's gain.
When we meet protagonist Matt Buchanan he's 16 years into a police career that's slowly killing him.
Unsolved cases haunt, he's suffering PTSD and downing six cups of Nescafe a day.
His way of coping is to put his work in a box and "bury it".
He's the solo-father of a teenage daughter - his wife killed in a car crash - and needs to be there for her but rarely is.
The victims and the brutality he sees "playback" in his head; when he can sleep he dreams crime scenes.
It's exacerbated by his frustrations with the justice system - "The courtroom is just where the facts get bent and twisted".
Victims are revictimised, bad guys set free and countless hours of good police work wasted.
But Buchanan's addicted to the chase.
"Churchill said something about being in the arena. That's where I needed to be. I couldn't watch from the sidelines - go to work, read the paper, watch the news - like every sane person. A life of that shit would've bored me to death."
This is not a novel of smart, well-fashioned sentences, or easily reducible bad guys.
In places the writing verges, uneasily, on the confessional - "every adult I'd ever met in the course of my work who had serious anger, personality or drug issues had been abused as a kid. Physically, sexually, emotionally - or a combo....".