In a dingy one-room apartment in London, old Princess Karukhina lies dead amid the squalor in which she lived. She had fled from Russia in the days of the Revolution, and had lived in obscurity and poverty with the one member of her family who remained alive, her grandson, Ivan. Now death brings her to the attention of Inspector Nightingale and Sergeant Beddoes of Scotland Yard. Very soon the Inspector begins to realize that the Princess did not die of natural causes. Her grandson is unaccountably missing, and the trunkful of magnificent jewels that she kept under her bed is empty. As Inspector Nightingale pursues his investigation he uncovers theft, double-dealing, and murder - and the tradition that contributed to the dignity of a royal family.