"It's easy to kill a man," you're told by your omniscient narrator (more on the second person later). "It's hard to kill a man well. People who do it well know this. People who do it badly find out the hard way. The hard way has consequences. Even the talented must be wary of that fact."

Malcolm Mackay's The Necessary Death of Lewis Winter  the first in a trilogy  is an intriguingly odd, remarkably original debut. It's the story of a murder, but it stands out in a crowded market by being virtually back to front. There's no quest for an unknown murderer, no race to avert a death  in fact, the detective character isn't even introduced until some way into the novel. Instead, we know from the start that Calum MacLean, "a twenty-nine-year-old gunman, living in Glasgow", is set up to be our killer. The Lewis Winter of the title is a lonely, incompetent, small-time drug dealer who gets mixed up with bigger things in an attempt to hang on to his (younger, unfaithful) girlfriend. Mackay jumps between viewpoints  Calum, the up-and-coming criminal organisation that hires him to knock off a potential threat in Winter, the detective on the job, the sleazy girlfriend of the planned victim  as events unfold.

What emerges is a bleak, depressing, frighteningly plausible picture of Glasgow's criminal underworld. The tension  and there's a lot of it; this is a book that it would be hard not to finish in one sitting  builds as Calum's plans near fruition, as Lewis goes about his life unaware, and as the realities of this dreary, dangerous world become clear.

Mackay's writing is cold, clinical, verging on the hardboiled. He specialises in short, snappy sentences. Usually truncated. Present tense. Odd again, but slightly addictive. Calum "doesn't drink. Not at all. He just copes. No great secret to it. No great skill. Just deal with it." He veers between third-person and second-person narration. Sometimes this works well, disturbs, implicating "you" in the crimes and investigations, drawing the reader deep into Mackay's characters' worlds. "The bang is always unsettling. It doesn't matter how many times you hear it." Sometimes it slips, a little. "Calum wears boxer shorts and a T-shirt to bed, in case you're wondering. You're probably not." Well, no.

The Scottish author, who has just turned 30, doesn't go in for flowery descriptions, or tugging at the heartstrings, or even moral judgments.Instead, he gives us a man who "has been knocked down enough times by life not to care much for it", who it's decided needs to die, and a skilful hitman who reads The Painted Veil, plays video games  Gran Turismo 5, "if you care"  who's hired to do the job. With small, quiet brushstrokes that it's hard to see building up, Mackay turns each of his characters into real people  people with interests and back stories and all the small, inconsequential things that make up a life  and ends up with a wholly believable and unnerving portrait of organised crime.