Agatha Christie's Marple - Season 5 Episode 2 -

Miss Marple finds herself spending the weekend at Chimneys, the stately home of Lord Caterham whose late wife was her cousin. The weekend has a diplomatic air to it as the Austrian Count Ludwig von Stainach is also there to negotiate a trade agreement with the British that will give the British access to iron ore. An important person goes missing, and Marple's search leads to a decades-old murder that might be connected to a mysterious diamond theft.