The story of diplomatic courier Tony Carleton, who's been entrusted with a secret message vital to the cause of International peace. En route to Geneva by train, Tony is drugged by sexy cabaret dancer Raquel, who promptly steals the message -- only to be murdered by sinister master spy Sebastian, owner of a posh gambling casino known as The House of a Thousand Candles.
Afraid of marriage, Simone (Mary Ellis) breaks off her long term engagement with her fiancé Paul de Lille (Tullio Carminati). Paul heads to the top of The Eiffel Tower with thoughts of suicide. In another part of Paris and also afraid of marriage, Mignon (Ida Lupino) breaks it off from her young lover (James Blakely). Despairing, Mignon also climbs to the top of the The Eiffel Tower intending to leap to her death. There she meets Paul and the two compare stories. After discussion, Paul dissuades her from leaping and the two conspire to make their respective partners jealous by pretending to have an affair with each other.
Marcia Calhoun, a talented but penniless singer, leaves her Southern home hoping to study opera in New York. Her instructor, Professor Didot, promises her a contract on the condition that she receive formal training in Italy for one year. Didot introduces Marcia to millionaire Philip Bradley, who offers to pay for her studies if she will accompany him to Italy as his mistress. Desperate for money, she agrees, but several months later, Philip abandons her.
Vincento Perez, the governor of the Portuguese colony of Exile, is an unscrupulous and brutal man who is hated by the natives. Furthering his schemes, Perez tries to force silk dealers out of business, and reveals his plans to government engineer Richmond Harvey in a letter appealing for the American's help.
Bank cashier Ramsey Latham is sentenced to prison for violation of the banking laws. On his way to the penitentiary, he encounters Hilary Kenyon, a young girl who speaks encouragingly to him. Later he is surprised to discover that Hilary is also a prisoner, having been found guilty of manslaughter for killing a man who attacked her.