Other murders follow, and Mercedes realizes the deaths are related to an old journal found in a castle they visited. Suspected of being the killer, Mercedes goes off on her own to clear her name.
She finds help along the way, but can she be sure of the helpers' motives, or are they after the same thing the killer is? Somewhere in Scotland there's a hoard of Spanish treasure and the answers to a puzzle about William Shakespeare that explain many questions surrounding his life. Can Mercedes unravel the clues to Shakespeare's blood before the killer catches up with her and lights her way to "dusty death"?