Castle Shade - Laurie R. King

Queen Marie of Roumania, granddaughter to both Victoria, Empress of the British Empire, and Alexander II, Tsar of Russia, is in need of Mary Russell and Sherlock Holmes' services. The queen, a famous beauty who has single-handedly transformed Roumania from a backwater into a force to be reckoned with, invites the pair to Bran castle. The ancient fortress sits on the border with the newly-regained territory of Transylvania, and was a gift to Queen Marie from her people.

The threat the queen fears is somewhat dubious: shadowy figures, vague whispers, dangers that may only be accidents. But a young girl is involved. So, putting aside their doubts, Russell and Holmes set out to investigate the mystery in a land of long memory and hidden corners - a land that had known Vlad the Impaler.

A land from whose churchyards the shades creep.