The opening pages of this historical mystery novel carry the reader into the midst of a demonic storm raging on the banks of the Severn River in Gloucestershire, England, in the early autumn of the year 1400. Unknown to the household of Lady Apollonia of Aust a tidal bore has surged up the Severn Estuary leaving in its wake a pre-dawn tide of dead lepers. One decapitated body discovered in a tidal pool is revealed to be an ancient adversary of the Lady.