At the behest of his enigmatic brother, Mycroft, Holmes is persuaded to investigate two unexplained, catastrophic train derailments which have caused the deaths of more than forty people. Why would a criminal wreck an express train?

A strange astronomer, the German Intelligence Service, a Russian yacht in the port of Aberdeen – the clues accumulate while the most homicidal lunatic in Britain remains at large. Something was afoot in Scotland that drew both King Edward VII and Mycroft Holmes from their lairs in Sandringham and Whitehall. A meeting with an emissary of the Czar?

The strenuous efforts of Sherlock Holmes to avert an international calamity and to bring to justice an evil assassin are here revealed for the first time in a tale the late Sir Arthur himself would have been proud of.