August 1923. All is quiet in the Holmes household in Sussex as Mary Russell works on academic research while Sherlock Holmes conducts malodorous chemistry experiments. But the peace quickly disappears as out of the past comes Dorothy Ruskin, an amateur archeologist from the Holy Land, who brings the couple a lovely inlaid box with a tattered roll of stained papyrus inside. The evening following their meeting, Miss Ruskin dies in a traffic accident...

"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....