A killer stalks his prey. The five precepts are laid down. The sixth will be his own...

DI Nathaniel Caslin has earned the freedom to run his case load as he sees fit, bypassing the hierarchical constraints with his specialist unit. Little does he know a deadly adversary is walking the streets of York. One who will push the team to their psychological limits...

Reluctantly agreeing to a joint investigation alongside a detective from the Drug Squad, Caslin is perplexed by the multiple homicides of a number of addicts. Poisoned by their own supply with no apparent motive, the killings appear gang related. The crime scene is filthy and forbidding with each victim having the index finger removed from their right hand after death. A planned mutilation? A trophy? Strategically placed among the dead is a blooming pink flower, the only beauty within a dark, macabre scene.

When a bank employee vanishes only to be found dead at the hands of a medieval stoning, Caslin's team are left with a puzzle to unpick. An index finger is missing and inside the victim's mouth, carefully placed and undamaged, are the petals of a small pink flower...

A serial killer is on a mission. Caslin must reach into the darkness in order to confront the most dangerous and determined killer of the age. One who seeks to build a monument to his efforts. One who desires to see the world perish in flames...