"A queen, a castle, a dark and ageless threat--all await Mary Russell and Sherlock Holmes in this chilling new adventure. The queen is Marie of Roumania: the doubly royal granddaughter to Victoria, Empress of the British Empire, and Alexander II, Tsar ofRussia. A famous beauty who was married at seventeen into Roumania's young dynasty, Marie had beguiled the Paris Peace Conference into returning her adopted country's long-lost provinces, single-handedly...

"With Mrs Hudson gone from their lives and domestic chaos building, the last thing Mary Russell and her husband, Sherlock Holmes, need is to help an old friend with her mad and missing aunt. Lady Vivian Beaconsfield has spent most of her adult life in one asylum after another, since the loss of her brother and father in the Great War. And although her mental state seemed to be improving, she's now disappeared after an outing from Bethlem Royal Hospital....