Peter Vaughan returns for his second story as the dastardly amoral detective Horace Dorrington.
A poor charcoal burner Jacques from France tells Dorrington a story of a stolen diamond, The Mirror of Portugal acquired by some shady means by his great grandfather during the French Revolution.
However many people in his family have died an unnatural death courtesy of sibling rivalry over the diamond. It is now in the possession of his cousin Leon who resides in London. Jacques wants Dorrington to steal the diamond.
Of course Dorrington is intrigued by the story done his own research and gathered that the diamond is valued at a princely sum of £100,000. He plans to steal the diamond for himself.
Dorrington takes some money of the poor Frenchman in a further meeting to listen to his tale and then sends him away telling him that his story is preposterous and returning the money.
It is all a ruse to show Jacques that Dorrington is not interested in the diamond when he actually is. It so happens cousin Leon loses the diamond stolen, it is stolen and someone mentions that he goes to see Dorrington who eyes a chance to be paid by Leon for his time investigating the matter.
Dorrington investigates the theft and finds an interesting lead but someone is unhappy with Dorrington's greed.
It is hard to root for Dorrington as he swindles everyone and even is mean to his staff who aid and abet him. Vaughn infuses some conniving charm but I was never persuaded by him.
The story is a little too simplistic as Dorrington encounters the Hamers. It is also just a tad convenient that Leon is sent to see Dorrington.
Jeremy Irons makes his television debut in a small role as a posh type. From his appearance it would be hard to believe that 20 years later he would win a Best Actor Oscar.