Dorinda Brown takes a job working for the wealthy Porlock family on a whim, and quickly finds it to be the hardest position she has ever had. The father, Gregory, is a charming tyrant—just the sort of man her aunt always warned her about. His wife is an overfed fool, entirely blind to the defects of her despicable son, and unsympathetic to the pain he causes his governesses.

All that Dorinda can stand, for she needs the job. But when murder comes to the Porlock house, it brings along much more unpleasantness. There is a question of blackmail, first of all, and a shocking realization about Dorinda’s past. All told, it adds up to a frightful mystery—the sort that only Miss Maud Silver, the governess-turned-detective, can solve.