The sixth in a series of medieval mysteries by the author of The Bartholomew Fair Murders, this story places the Chelmsford clothier Matthew Stock and his canny wife, Joan, in the midst of a rather plodding bit of mayhem. At the express wish of Queen Elizabeth, the pair investigate the questionable drowning of the lord of Thorncombe Castle. Sir John Challoner had just returned home from warring with the Irish when he was found sitting bolt uprightbut ''drowned dead''in a small boat at the edge of the man-made lake on his grounds. His irascible housekeeper Moll Fludd and her weak-willed husband Cuth are willing to lay his death and the subsequent murders of two Irish servants at the feet of the Black Keep ghost, but the Stocks are reluctant to credit this handy fiction. When rumors surface of a treasure stolen and hidden by Sir John, Matthew believes they are getting closer to the truth, but it's Joan who supplies the last puzzle piece that points to a worldly killer.