Silva Varescu, a self-sufficient and professionally successful cabaret performer from Budapest, is about to embark on a tour of America. Three of her aristocratic admirers, named Edwin, Feri and Boni, prefer her to stay. Edwin, unaware that his parents have already arranged a marriage for him back home in Vienna, orders a notary to prepare a promissory note of his expected marriage to Silva within ten weeks.

The Second World War is over. The post-war Germany is divided into several responsibility zones. Still many Russian people languish in camps located in the American zone. Though former allies are in no hurry to let them off to the motherland, and even try to enroll some of them. The American intelligence agency gets to know that they've got a daughter of one of the West Germany cities commandant, whose brother is a famous soviet rocket engineering designer. They plan a crafty operation on the discrimination of the Russian colonel and introduction of the niece into the uncles design office. The Russian Intelligence service is also aware of the Americans interest in the designers works. The special department colonel Lartsev is coming from Moscow to Germany to prepare a reciprocal operation.