DCI Tony Clark finds himself assigned the unenviable task of investigating his own station when Scotland Yard suspects corruption. His first target is a ring of officers who are taking kickbacks from laundered drugs money.

When a youth is shot by police on a troublesome estate, years of resentment within the community flare into violence, to the concern of Chief Supt. Jameson.

A complaint of sexual harassment by a W.P.C. against a black sergeant, and an accusation of bribery, reveal widespread prejudice within a station. With his own personal life in tatters, is Det. Supt. Clark the right man to investigate the case?

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.

After a brutal armed robber is released, DCI Tony Clark investigates the officer accused of bending the rules to obtain his conviction.

Tony Clark is called in to investigate claims of police brutality when a full-scale riot erupts at a picket line. Given no help by Commander Neame, he approaches journalist Molly Cope for information and soon begins to suspect a police cover-up.

Det. Supt. Clark is ordered to investigate outstanding complaints against P.C. Norton, an officer killed in the course of his duty. Should PC Norton be allowed to rest in peace?

Det. Sgt. Markham is accused of taking a bribe. Meanwhile, Clark's lover, W.P.C. Jenny Dean, is under pressure over her part in the Michael Carswell affair.

Det. Supt. Clark is caught between Customs and Excise and the river police during a case of extortion, drug smuggling and illegal immigration. W.P.C. Jenny Dean finds herself under investigation over her part in the Michael Carswell case.

A youth dies in police custody, but was it really a suicide? Det. Supt. Clark learns some uncomfortable truths about girlfriend W.P.C. Jenny Dean.

A police superintendent is caught kerb-crawling in King's Cross. Det. Supt. Clark uncovers murder, blackmail and pornography, and his investigation could finish some careers. The investigation into the Michael Carswell case has tragic consequences for W.P.C. Jenny Dean.

Commander Huxtable has been suspended. Det. Supt. Clark is determined to discover why his lover, W.P.C. Jenny Dean, committed suicide, but his enquiries lead back to C.I.B. Finally, he confronts an unexpected enemy aboard H.M.S. Belfast.