"If we are right about this, the stakes are higher than anything I’ve ever faced." Gangsters have infiltrated Edinburgh. MI5 are on their case and, unknown to DCC Bob Skinner, have set up a drug-dealing sting to flush them out. The resulting mayhem throws everyone into confusion until they realize the gangsters are preparing a hit on one of the Royal family. Meanwhile two policemen mourn the loss of a son and a daughter in mysterious circumstances, and another witnesses his son being abducted. Is someone trying to wreak revenge on the police force? Are the crimes linked?