Holmes and his faithful sidekick are contacted by the mysterious and duplicitous Prince Regnant of Bulgaria, following the theft of an ancient and sacred manuscript. Holmes is tasked with finding the manuscript, and by delaying the outbreak of World War One.
So, plot set, the trusty duo set off for Bulgaria, travelling through beautifully described landscapes. As one would expect, the story is not as simple as it at first appears, and what follows is a tale of murder, greed, and vampires. There are the requisite unexpected twists and turns.