In the middle of his second opera, Lulu, Alban Berg inserted a silent movie that is accompanied by film music. Although Berg gave precise instructions for the film scenario and its association with the music outlined in the Particell, many directors omit the film in stage performances. However, the film is essential to the opera dramaturgically because it fills the gap that Wedekind had left in between his two dramas, Erdgeist (‘Earth Spirit’) and Die Büchse der Pandora (‘Pandora’s Box’). Berg initially considered having a speaker narrate the intermediate story but decided on a silent film which depicts the events. In this article, the film and its music are analyzed to show how they together fulfill three functions: as a narration of the missing link; as a mirror axis for the opera’s symmetrical design; and as the pivot of the whole opera.