A mysterious, coded message is received, a warning of imminent danger, drawing Sherlock Holmes and the faithful Dr Watson into a tale of intrigue and murder stretching from 221B Baker Street to an ancient moated manor house to the bleak Pennsylvanian Vermissa Valley. Faced with a trail of bewildering clues, Holmes begins to unearth a darker, wider web of corruption, a secret society and the sinister work of one Professor Moriarty.