Stephan Gregorovitch, the unwilling king of a bankrupt Ruritanian country, along with his hucksterish chancellor and musically-inclined bodyguard, travel incognito to London for some fun.
A pretty young lawyer discovers that her father needs an expensive operation to save his life. She goes to a nearby city and takes out an ad offering to marry whoever will pay her $5000, the cost of the operation.
Guests at a luxury hotel are horrified when they witness a man literally "disappear into thin air." The vanished man's relatives hire a detective, who goes to the hotel to investigate the disappearance.
Scheduled for demolition, Hotel Continental has seen 50 years of romance, intrigue, and tragedy. The last night attracts many nostalgic patrons, including a gangster planning to grab the loot that he hid there many years ago.