Deputy Chief Constable Stephen Blackton is called into the Met to investigate two possible scandals. Known as Blackdog, he has a well-deserved reputation at pursuing corrupt police officers. The first case is the Cripps shooting where an unarmed man was shot by an armed police squad. Although a coroner's enquiry found no fault, Commander Blake has raised doubt as to DCI Mike Hedges' role. The case takes a particular turn when one of the armed officers, Graham Warner, is found dead. Blake also finds herself under investigation by Blackton over her sexual relationship with accused serial killer James Lampton. With the trial approaching, there is great concern as to the adverse publicity that will result.