Det. Supt. Clark follows up an allegation of police brutality after an old man claims to have seen a prostitute attacked, but an influential detective ensures that the enquiry is obstructed.

Det. Sgt. Connell's cover is blown while investigating a hostile police station. Det. Supt. Clark is caught up in a murder case with both personal and professional implications.

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.