After a hostage rescue goes wrong, superintendent Sandra Pullman (Amanda Redman) is put in charge of unsolved crimes. With little resources and no back-up she decides to recruit three ex policeman.
However times have changed, unlike her new recruits...
Jack Halford (James Bolam) is yet to get over the loss of his wife, Brian Lane (Alun Armstrong) is over obsessed and over medicated, and Gerry Standing (Dennis Waterman) is not quite the ladies man he used to be.
They may have the experience but it's not like the old days. Not only are they chasing criminals, but they are having to deal with a new police force which does not always appreciate their old style policing.
The series title is taken from the popular expression "You can't teach an old dog new tricks". The "old dogs" are successful in adapting their skills and experience to modern policing, with their knowledge of past cases proving especially useful.
The series is produced by Wall to Wall.