In postwar Vienna, Austria, Holly Martins, a writer of pulp Westerns, arrives penniless as a guest of his childhood chum Harry Lime, only to learn he has died. Martins develops a conspiracy theory after learning of a "third man" present at the time of Harry's death, running into interference from British officer Major Calloway, and falling head-over-heels for Harry's grief-stricken lover, Anna.
Director Richard Anden and his screenwriter take a cruise on a luxury liner, avoiding all feminine attempts to get a movie contract, including the ship singer. When he unexpectedly discovers that a beautiful passenger is involved in a murder mystery and chased by the police he'll try to save her from jail. Yet everyone has a secret in this Austrian musical comedy.
Young Count Georg Wolkersheim is sent to the Congress of Vienna to represent the interests of his country, Reuss-Schleiz-Greiz. Tensions arise between the count, his wife Melanie, and their two chamberlains, and when the four attend a court ball, Melanie leaves Georg, assumes the identity of a famous actress, and attracts the affections of Crown Prince Ludwig of Bavaria.
The young, attractive Inge Wagner becomes acquainted with Herbert Koch during the Berlin Olympics, his flight officer insignia having first caught her eye. Sparks fly immediately between the two and they soon decide to marry. But Herbert is called off on a secret mission in Spain.
Vienna is celebrating New Year’s Eve 1913/14. It is the year, which will see the outbreak of the First World War. In Hotel Sacher, the mood is excellent; and although the political atmosphere is charged, there’s an undercurrent of hate and intolerance in the air. It is with this background that Nadja, a Russian spy, meets the Austrian civil servant Stefan. He loves her, but comes under suspicion of being an agent because of this love.
The poor, lower-class girl Eliza Dolittle sells flowers at London’s St. Paul’s Cathedral to passers-by. Her plain jargon, her headstrong way of expressing herself, fascinates the briefly passing-by language researcher and phonetics teacher professor Higgins. He meets a good acquaintance, colonel Pickering, who is also interested in science, and makes a wager with him: Higgins bets that he can accomplish that, within just six months, he can turn the squalid girl with grubby looks into a gentle lady of the London society with splendid manners and a likewise pronunciation. Eliza may not know what’s coming for her, but after some persuasiveness, she agrees to move into the fine house of the professor.
Das Lied ist Aus (The Song Is Ended) is a typical early-talkie German musical in every respect, save one. The story, concerning the lives and loves of show folk, ends unhappily -- and surprisingly so. The doleful denouement didn't seem to have much effect on the film's box-office appeal, since Das Lied ist Aus proved a major moneymaker.