Agatha Christie's Poirot Season 3 Episode 8

The Theft of the Royal Ruby

Poirot prepares to spend a quiet Christmas on his own with a box of chocolates, but he has to give up his plans when the British government asks for his urgent help. Prince Farouk, a young member of the Egyptian royal family visiting London, has lost a famous ruby, and this is deemed to be a matter of national security.