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...