Before slipping into well-earned retirement, Sherlock Holmes has prevailed upon his long-time companion Dr Watson, his landlady Mrs Hudson and Inspector Lestrade of Scotland Yard to join him in a farewell tour of the British Isles. For the first time ever they will re-enact one of the detective's most baffling unrecorded cases - The Case of the Prime Minister, the Floozie and the Lummock Rock Lighthouse - an affair upon whose outcome the security of Europe once hung by a thread. Shrouded in secrecy until now, this case has finally been approved by the government for public disclosure.

It is also understood that Mr Holmes has been entrusted by Her Majesty with the conveyance to the Tower of London of the fabled Satsuma Stone, stolen from the crown of William of Orange in the seventeenth century and only recently discovered in a midden in Maastricht. It is expected that the evening will include a glimpse of this priceless gem; in which case, one can only be thankful that Professor James Moriarty, the Napoleon of crime, fell to his death at the Reichenbach Falls. Or did he? Or is he still alive, planning another deadly strike as he lurks, unseen, in the wings...?