Charlie Barlow's former boss Det. Chief Supt. Robins invites him to return North to re-investigate the murder of Mary Bradshaw, eight years before. Her missing bag has been found during redevelopment opening several new leads.
Det. Insp. Cook is attempting to second guess where a robbery gang will strike next. There appears to be a pattern of two robberies, close together, on the same day. Cook now needs to work out which two targets are next.
Crime Squad looks into a casino that can't be making any money but among the people do go there are target criminals. Evidence is available to arrest several men but Det. Chief Supt. Barlow wants the man in charge.
A hole in a fence at a company that makes brake linings peaks the interest of Special Branch. The factory has too much security for what it claims to be making so Det. Chief Insp. John Watt seconded to investigate on their behalf.
Det. Chief Supt. Barlow is tipped off that an organised gang of shoplifters are heading to the Wyvern area. Eddie Nevin is the head of a family of five but the constant pressure is now beginning take it's toll.
County Constabulary arrest small time crook Edward Casey for receiving. Casey is a target of Crime Squad believing he can provide information something far more serious when he dropped off a letter to an office under observation.
Tommy Ford is taking over the protection rackets from Joe Breem using the muscle of Abel Jackson. After his club is wrecked, Breen retaliates with an hit and run attack on Jackson. D.C.I. Watt attempts keep the lid on affairs.
An allegation of corruption against a senior officer forces Mr Gilbert to take an absence to investigate the matter. Barlow is promoted while John Watt finds his nose out of joint when he is over looked for Arthur Jones from County CID.
Welsh Nationalists move into the Wyvern area to blow up the local water mains. The Nationalists aim is to gain equal status for the Welsh language alongside the English. Special Branch is sent to aid Crime Squad.
Arthur Jones first day temporary head of Regional Crime Squad. He is keen to gather information on a former Polish radio operator called Anderson. His operation falls foul of government secrets and along with Barlow politely warned off.
Det. Con. Ben Box recent erratic behaviour is beginning to spill over from his home into his work. His wife is so worried that she asks Harry Hawkins for help but panic sets in when Box vanishes and can't be found.
Charles and Muriel Weston steal goods worth £16,000 from fellow guests at the Penton Range Christmas party. D.C. I. Watt believes this is a professional job and thinks he can smoke out the couple he believes to be guilty.