Vicky Barton and her brother Johnny travel from Naples to visit the 1889 Paris Exhibition. They both sleep in seperate rooms in their hotel. When the she gets up in the morning she finds her brother and his room have disappeared and no one will even acknowledge that he was ever there. Now Vicky must find out what exactly happened to her brother.
Jean Simmons
as Vicky Barton
Dirk Bogarde
as George Hathaway
David Tomlinson
as Johnny Barton
Marcel Poncin
as Narcisse
Cathleen Nesbitt
as Madame Hervé
Honor Blackman
as Rhoda O'Donovan
Zena Marshall
as Nina
André Morell
as Doctor Hart
Betty Warren
as Mrs. O'Donovan
Eugene Deckers
as Day Porter
Felix Aylmer
as British Consul
Austin Trevor
as Police Commissaire
