The beginning of the 20th century. Famous singer Emilia Marty arrives on tour in a European city. At the same time, the Supreme Court intends to close the Gregor-Prus case, a lawsuit that lasted several decades. Albert Gregor unsuccessfully tries to seize the inheritance of Baron Joseph Prus, but cannot prove that he is his heir. Emilia Marty unexpectedly intervenes in the process, reporting the whereabouts of documents proving the family kinship of Albert Gregor and Prus.