The murder of Mary Russell

"Mary Russell is used to dark secrets--her own, and those of her famous partner and husband, Sherlock Holmes. Trust is a thing slowly given, but over the course of a decade together, the two have forged an indissoluble bond. And what of the other person to whom Mary Russell 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. What Samuel Hudson tells Russell cannot possibly be true, yet she believes him--as surely as she believes the threat of the gun in his hand."--