A long time ago, the great master Leonardo da Vinci worked on a unique invention, which he was never able to bring to perfection... Nowadays, the great computer scientist Anton developed his idea and created a computer program worth millions of dollars... Katya's nephew Lenchik ran to his aunt for help: his friend disappeared. Before he disappeared, Anton hid his program somewhere on the Internet. And he sent out leads to the addresses of ladies who married foreigners through the marriage bureau, where he worked part-time. An aunt and nephew go to Europe, and there it turns out that they have very dangerous competitors. A cascade of chases and adventures carries Katya and Lenchik non-stop through the Venetian canals, the narrow streets of Verona, the avenues of Madrid, the snowy mountains of the Sierra Nevada... Further and further - in search of a miracle...