A suspect being held under CI5's supervision is found dead in his cell - apparently after a fatal blow administered by Doyle. A public inquiry ensues and an influential lawyer calls for CI5 to be shut down. It's left to Cowley in fighting to save the organisation he founded.

A virtual police state has been imposed by a local Chief Constable, resulting in a supposedly almost crime-free city. But that is because all the crime is taking place behind the scenes by the police officers themselves - who will think of nothing of imposing on suspects' rights in their pursuit of 'zero tolerance'. Bodie and Doyle become hunted men when they visit the city and begin to question the rather unorthodox methods of action taken by the local constabulary.