In this romantic comedy, an aspiring socialite heads for a vacation in Monte Carlo where she befriends a wealthy widowed duchess and then begins blackmailing her after she steals a scandalous letter.
A mysterious criminal known as The Whispering Shadow commits crimes by means of a gang he controls by television and radio rays. Jack Norton, whose brother was murdered by The Whispering Shadow, suspects that the eerie Professor Strang - whose ghostly wax museum contains figures far too lifelike - may be involved in the crimes.