The famous American film writer Douglas Dutchman arrives in Germany aboard the Zeppelin. The press is there, as is the producer of his film, Siegfried Heidkamp, and the German star Brigitte Barett, who is to be his partner. After a triumphant welcome, Douglas Dutchman is invited to open an exhibition of jewelry belonging to Heidkamp's wife, Romy. During the rehearsal of the ceremony, Dutchman claims that the showpiece, the famous Ka-Hi-Dor diamond, is a fake. Everyone is stunned.