In jeopardy

If you had been Hugh Hildebrand, but lately fallen heir to his ancestral estates, would you have surrendered your fair possessions to an Unknown Terror? Or would you have chosen, as Hildebrand did, to contend against the mysterious force that brought death to each succeeding lord of the manor? Hildebrand's predecessor had been sitting in his quiet library when he was struck down by a mysterious power. There was something waiting in that peaceful room waiting in sinister silence to kill the newcomer. Betty Hildebrand finally found the key to the riddle, but it was only at the last minute that she learned how to use it.