A man is accidentally knocked down outside 221B Baker Street by a carriage. His dying words claim he has seen a man rise from the grave. At the same time, a visitor arrives with a mystery of unparalleled international importance. The Viscount Wrexham is missing, presumed dead, in strange circumstances. In the North, rumours stir of a dead man haunting the moors. Broomheath Hall is beset by ghostly lights and spectres. What does it all mean? Can arcane knowledge bring people back from the dead? The redoubtable Mrs Hudson – Sherlock Holmes' housekeeper and the Great Detective's best-kept secret – and her assistant Flotsam are once again thrown into dark adventure full of gripping twists and murderous intrigue. Together with Holmes and Dr Watson, they must race against the forces of darkness to uncover the truth behind the mysterious document known as the Lazarus Testament.