Hit and Run — Doug Johnstone

Driving home from a party with his girlfriend and brother, all of them drunk and high on stolen pills, Billy Blackmore accidentally hits someone in the night. In a panic, they all decide to drive off.
But the next day Billy wakes to find he has to cover the story for the local paper. It turns out the dead man was Edinburgh's biggest crime lord and, as Billy struggles with what he's done, he is sucked into a nightmare of guilt, retribution and violence.
From the author of the acclaimed Smokeheads, Hit & Run is another pitch-black psychological thriller.