When Teddy Edison, youngest son of the late Thomas Alva Edison, asks Tony Del Plato to investigate some odd occurrences at the castle laboratory of millionaire inventor John Hays Hammond, Jr., it is a request more for Tony's much needed change of scenery than out of any real necessity. While leaving West Orange, New Jersey, might prove to be therapeutic following the recent events in Tony's life, little could anyone foresee that this forced vacation on the restful and beautifully rocky coastline of Massachusetts would ultimately involve local gangsters, murder, and espionage.

Adding to the confusion is a scheduled remote radio broadcast from the castle not to mention an unexpected rivalry between M.G.M. publicity girl Edie Koslow and Paramount actress Marjorie Reynolds, who is visiting after a War Bond tour in Boston to promote her new film, Holiday Inn.