The series focused on the police station and crime in the Victorian town of Matlock and the surrounding district, and the backgrounds and personal lives of the main policemen.
Series writers had a reference manual giving full details of the town’s geography, amenities, social structure, etc., as well as that of the surrounding area - neighbouring towns included Wilga, Chinaman's Creek, Possum's Creek and Burrabri, and there was an offshoot of the Great Dividing Range called the Candowies.
A notable guest star was George Lazenby who appeared in a 1974 episode "In the Name of the Queen"[6] (inspired by the case of Ronnie Biggs and the Great Train Robbery).
Other noted Australian actors who made early appearances on the series include Andrew McFarlane, Bruce Spence, Jack Thompson, Robert McDarra, Judy Morris, Diane Craig, Briony Behets, Penne Hackforth-Jones and Sigrid Thornton.
During the filming of a pursuit-sequence for episode 36 ("End Of The Road") in August 1971, a police vehicle driven by a principal actor struck and instantly killed a 21 year-old member of the camera crew, Colin Enor (or Ennor/Ennoh)[8] after losing control while negotiating a gravel bend.