A Dark So Deadly

A Dark so Deadly is a 2017 detective fiction novel written by Stuart MacBride. Set in the fictional town of Oldcastle, it follows the Misfit Mob - a detective unit of Scottish police made up of officers who were sidelined from mainstream cases for various reasons. Tasked with what is seemingly a case of theft of a mummy from a museum, they later find that the found body was the work of a serial killer who mummifies his victims. The story proceeds to chronicle their attempts to find the perpetrator.

While a standalone novel, the setting of Oldcastle and some of its characters are taken from two Ash Henderson novels (Birthdays for the Dead and A Song for the Dying). A Dark so Deadly was the first of Macbride's seven books that did not debut at number one in the book charts.

Plot
Detective Constable Callum MacGregor is in the Misfit Mob. This is where Police Scotland deposit their outcasts, troublemakers and those whom it wishes to get rid of but cannot. Callum is in the Misfit Mob because he screwed up the forensics at a crime scene, which allowed a known killer to avoid conviction. Everyone thinks he accepted a bribe from the killer to deliberately contaminate the scene. Trouble is, MacGregor didn't ruin the crime scene; it was his pregnant girlfriend, for whom MacGregor took the blame so she would not be sacked and lose her benefits.

As a member of the Misfit Mob, MacGregor contends with police finding his mum's remains (25 years after she went missing) and finding out that his long lost twin brother is a serial killer who is mummifying his victims. The haiku-speaking sergeant in charge does not welcome MacGregor and his supervisor is revealed to be the real father of MacGregor's child.