When Brett introduced us to this humorous not-quite-cozy series four novels ago, the indomitable Mrs. Pargeter, a mixture of Miss Marple and Murph the Surf, had just become a widow. Confronting her first corpse, she discovered that part of her late husband's legacy was the devotion of a cadre of larcenous but fiercely loyal "associates," whose combined street-smarts were the match of any murderer's. In her latest brush with sudden death, Mrs. P. decides to…