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.

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.

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.