Following her Oxford lecture on the unsolved murder of Henry Darnley, husband of Mary Stuart, historian Ann Dukthas (yes, the character shares the pseudonymous author's name) learns from Dr. Nicholas Segalla, an appreciative member of her audience, that he has information that will clear Mary of the long-standing suspicion that she connived in Darnley's death in order to marry the Earl of Bothwell, her alleged accomplice. And what information it is, since Segalla claims to have met Mary in his earlier life as Father Nicholas Segalla, sent under cover by Archbishop Beaton to Mary in order to protect her against the possibility of civil war raised by the rift between her and her philandering husband -- and by the sinister designs of the Raven Master, a provocateur acting on behalf of Queen Elizabeth to fan the flames of dissension within Mary's ruined court. In a narrative dated 1567, Segalla recounts his fruitless attempts to warn Mary of her danger, the explosion of Darnley's lodgings at Kirk o'Field, and the discovery of Darnley's unmarked corpse, together with that of his squire Taylor, in the adjoining orchard. Who had access to the gunpowder used in the explosion, who were its intended victims, and why and how was Darnley killed away from the scene of the blast? Segalla's narrative answers all these questions, but without any of the fanfare or flourishes that would win a larger audience than latter-day partisans of Mary's cause. And the fanciful conceit of Segalla's multiple incarnations seems pointless, except presumably as motivation for sequels in other historical periods.