Performed by Julian Rhind-Tutt and Derek Jacobi.

"Days after the encounter at the Swiss waterfall, Pinkerton detective agent Frederick Chase arrives in Europe from New York. Moriarty's death has left an immediate, poisonous vacuum in the criminal underworld, and there is no shortage of candidates to take his place--including one particularly fiendish criminal mastermind. Chase and Scotland Yard Inspector Athelney Jones, a devoted student of Holmes' methods of investigation and deduction originally introduced by Conan Doyle in The Sign of Four, must forge a path through the darkest corners of England's capital--from the elegant squares of Mayfair to the shadowy wharfs and alleyways of the London Docks--in pursuit of this sinister figure, a man much feared but seldom seen, who is determined to stake his claim as Moriarty's successor" --