The history of the royal family contains many instances of unexplained illnesses and premature death - George III's madness, the downfall of Mary Queen of Scots and Rasputin bringing down the Russian throne can all be linked to Queen Victoria. This episode explores how, in trying to preserve the bloodline, the monarchy may have spread genetic disease far and wide - from porphyria wreaking havoc with British royals to haemophilia finding its way from Buckingham Palace to Moscow.