After a very close call on the Norfolk Fens Harriet White is about ready to hang up her deerstalker and settle into life in the basement of the Baker Street building society where she works. Until she discovers a letter in The Times newspaper challenging Sherlock Holmes to prove his status as the world?s greatest detective by solving an impossible mystery. The letter signed Professor James Moriarty advises Holmes that the crime will be committed within the following seven days. There will be no further clues - Holmes himself must deduce which crime is the correct one to investigate. Dismissing the letter as a prank Harry goes about her business until news breaks of the theft of a valuable jewel collection from a safe in an apparently locked room in a Mayfair townhouse. Intrigued in spite of her misgivings Harry dons a disguise and investigates. But as she begins to unpick the puzzle a body is found. And now a stranger and far more deadly mystery begins to unfold around her...
