Ver Cuevana 3. "Silver lute", the choral society of the Vác Engine Works, led by Réz, the conductor, is preparing for its 25th anniversary. All the important members of the society, among them Seregély, a magician, are, at the same time, all "fathers" of Zsóka, daughter of a former colleague, who has been killed in an accident, and whom they then adopted.