A millionaire with a mysterious fiancee hires a detective to discover the truth about her past.

Sylvia West is a young poetess engaged to Frederic Summers, an eccentric millionaire. Summers, a man who always fears he is being loved for his money, decides to make a small check on his prospective bride. The results of this check completely shock him. Not one fact matches 'his' Sylvia. Intregued and bewildered, Summers hires detective Alan Maklin and has him make a thorough investigation on 'Who Is Sylvia.'—filmfactsman