In Edinburgh, evil is just one floor away …

Fraud investigator Cat Thomas has bought a beautiful 18th-century apartment in Edinburgh, far from the dangers of her life in Florida. But when the neighbour from hell arrives, her nightmare begins.

Desperate for a decent night’s sleep, Cat dreams of ways of killing him. And when her darkest thoughts become reality - and her neighbour ends up very, very dead - her life takes a sinister new turn.

Is this heaven? Or hell? Is she being framed for murder? Is her devilishly charismatic new neighbour upstairs responsible? And why are so many people around her suddenly being so gruesomely dispatched?