It's 1989 in London, the Cold War between East and West is finally coming to an end, and thirteen-year-old Milly has a school project to find out about her family history. But all she knows is that her grandad was a doorman at the Savoy - and that, long ago, he was supposedly a Russian prince, back when Russia still had princes. Could that really be true?
So, when she discovers an old diary written in Russian, she enlists the help of her schoolfriend Ilya, whose family has fled the Soviet Union, to unravel Nicolai's story.
As they piece together the unbelievable details of his escape from the Red Army and the hardships, love and kindness he encountered as he made his way across Europe, Milly sees an opportunity to heal the tragedies of the past - with unexpected consequences.