Malcolm Fox and his team are back. They've been sent to Fife to investigate whether fellow cops covered up for a corrupt colleague, Detective Paul Carter. Carter has been found guilty of misconduct with his own uncle, also in the force, having proved to be his nemesis. But what should be a simple job is soon complicated by intimations of conspiracy - and a brutal murder committed with a weapon that should not even exist.

The spiralling investigation takes Fox back to 1985, a year of turmoil in British political life. Terrorists intent on a split between Scotland and the rest of the UK were becoming more ruthless, sending letter-bombs and poisonous spores to government offices, plotting kidnaps and murder, and trying to stay one step ahead of the spies sent to find them. Fox has a duty to get at the truth, while the body count rises, the clock starts ticking, and he fights for his professional and personal life.