Mary Russell is used to dark secrets--her own, and those of her famous partner and husband, Sherlock Holmes. But what of the other person to whom she has opened her heart: the couple's longtime housekeeper, Mrs. Hudson? Russell's faith and affection are suddenly shattered when a man arrives on the doorstep claiming to be Mrs. Hudson's son. And though what he tells Russell cannot possibly be true, she believes him--as surely as she believes the threat of the gun in his hand. In a devastating instant, everything changes. And afterward, a pool of blood stains the floor, the smell of gunpowder hangs in the air, and most shocking of all: the grim clues point directly to Clara Hudson. Or rather, the woman she was before Baker Street. Now, to uncover the truth, a frantic Sherlock Holmes must put aside his anguish and push deep into his housekeeper's secrets--to a time before her deception, before her crimes were buried. There is death here, and murder, and trust betrayed. And nothing will ever be the same.