Sgt. Cannon (Tommy Cannon) and PC Ball (Bobby Ball) run the police station in the quiet town of Little Botham. When the station is threatened with closure due to a lack of crime, they decide to invent some crimes to justify their existence. When they try to steal a painting from a local rich businessman (Roy Kinnear), they accidentally stumble across a gang of real art thieves who have just stolen £1 million worth of paintings. It is up to the two bungling cops to stop them escaping with their haul.