The old cliché is 'a dark and stormy night', but here there is no storm - just fog. And old clichés are the order of the day in "The Shadow", a creaky antique that is really fun and absorbing in spite of itself. Motion pictures became far too sophisticated and technological for this one, unless you yearn for a time when movies, and life, were simpler.
The Shadow is one bad dude, a blackmailer Scotland Yard has been trying to nab for some time. He is responsible for some suicides and murders, and finally shows up at the home of the Chief Inspector, along with various and sundry guests and visitors (this, of course, creates a lot of suspects). This story was based on a play, and something must have been lost in the translation because, as reviewer dburroughs above states, there is very little logic and a great deal of contrivance involved.
Nevertheless, it is very enjoyable if you just go with it and don't ask questions. And Henry Kendall, who plays a silly-ass Englishman/friend of the family, is worth the price of admission.