In the first series, two ballroom-dancing regulars discover a tragic secret; Dangerous is assigned to look after the victim of a vicious burglary; and the detective is saddened by the death of a harmless local tramp known for his penchant for collecting waste paper.
In the second series Dangerous investigates the death of a wealthy painter. The detective is called out to settle a routine dispute over a leylandii hedge; looks into the death of a medical researcher who was found drowned; and finds his car has been clamped while he's been engaged in official duties.
The third series sees Dangerous looking into the death of a man at a college reunion. The detective investigates the murder of a former soldier; the death of a washed-up 1970s rock star; and the demise of a stock-car driver during a world championship race.
As series four unfolds a recently released criminal is murdered as he prepares to publish his explosive memoirs. Dangerous investigates the murder of a pornographic film-maker; the death of a veteran comedian on stage; the murder of a chauffeur; and a businessman found stabbed to death.