Heavy plant equipment is stolen from a new motorway extension. Hawkins leads an undercover operation to discover who is involved. Mr Gilbert's return to puts an end to Det. Chief Supt. Barlow's first command job.
W.D.S Barbara Allin stumbles on a car ringing outfit using a stopover car park. With her boyfriend driving a decoy car she unwittingly treads on the toes of D.C.I. Watt's investigation into the same gang, passing dud checks abroad.
Crime Squad are tipped off that escaped robber Jack Marshall is hiding out at a remote farm in the Welsh hills, planning a new job. Allin and Morgan go undercover, has hikers, to confirm Marshall's presence.
Det. Chief Supt. Barlow is brought into a nine week old murder inquiry of bus driver Alfred Cameron. The investigation has become stale, unmotivated officers go through the motions. Barlow decides it is time shake things up.
Tramp Dicky Bird overhears a conversation about the sale of gelignite to the unassuming Stanley Mellish. The original seller is warned off but Yob muscles into the sale after beating Bird to death. But what are Mellish's real motives?
Barlow and Cook recover a set plans from a gang who on a previous raid targeted whisky. They discover that their plan is a flow chart pointing to what has to be done before they can proceed. They now to find the target.
With seventeen burglaries in the same area as a reform school for boys, Det. Chief Insp. Watt is convinced there is a connection. Headmaster, Mr Carter in convinced no boy can get out night but Watt thinks they have found a way.
Barlow and Gilbert are at loggerheads over the prison release of serial sex offender Michael Madden. The pair disagree over whether Madden is reformed but when he loses surveillance officers there is panic that he will strike again.
John Watt gets a tip off that former jailbird Ted Fisher is planning a job worth £20,000. While visiting a former colleague Jammy, now a private eye, he spots a Fisher associate Durrell. Jammy is keen to help but Watts has doubts.
Interpol make a request for help to find how high quality fake £5 notes are getting from Germany into England. Det. Chief Supt. Barlow is put in charge of the case with information that they coming through the Bristol area.
Local C.I.D. find a stolen van equipped enough tools for either a factory or bank robbery. Observation gives them the arrest of George Anderson, who claims to be a minor player but his record implies a much a bigger role.
An error of judgement by Det. Chief Supt. Barlow allowed bank robber George Prenter to slip through his fingers. An informant now tells him that Prenter will be brought into the country from a private airfield by Harry Owen.
D.S. Hawkins is investigating illegal immigrants at the docks when a woman's body is discovered murdered. W.D.S. Allin believes it could be the body of missing girl Marilyn Edwards but the dock security deny she ever entered.