A high profile M.P. is caught with his trousers down, and suspicion falls on his police protection officers. As more revelations appear in the tabloid press, Clark suspects a smear campaign.

An intruder is shot dead at a Territorial Army base. Clark is forced to accept help from Angela Berridge, an official from the Home Office, and finds that the activities of MI5 and Special Branch undermine his investigation.

A peaceful demonstration about council service cuts goes tragically wrong when the mounted police are called in to disperse the demonstrators. Clark's team is brought in but their activities are hindered by the chief constable heading the investigation.

An assistant chief constable is accused of sexual misconduct, and Det. Sgt. Connell's friend Kate is implicated. Det. Supt. Clark's search for a missing tape brings him back into contact with Angela Berridge.

Chief Supt. Trevor Dunne, recently cleared by an enquiry, faces another when a convicted criminal provides fresh evidence. Det. Supt. Clark is torn between duty and loyalty towards a highly regarded officer.

Det. Sgt. Connell's professional and private lives come into conflict when CIB investigate a police officr suspected if being the driver involved in a tragic hit-and-run incident. Det. Supt. Clark, meanwhile, is becoming increasingly obsessed with Angela Berridge.

Det. Insp. Naylor faces a disciplinary hearing when he is caught moonlighting for a security firm to raise funds for the treatment of his terminally ill wife, Joyce. Det. Supt. Clark confronts Angela Berridge over their relationship.

Det. Supt. Clark investigates the involvement of Special Branch in the 'execution' of police informant Declan Harris, and gets the chance to settle old scores with Det. Chief Supt. John Deakin.

Det. Supt. Clark is gunning for Det. Chief Supt. John Deakin, now with Special Branch, and is led to Trevor Bull, a victim of a police shooting years earlier.