Tanya, Kostya, Misha and San Sanych go on vacation to the south in one compartment of the train Moscow – Yuzhnogorsk. Kostya gives Tanya a lottery ticket and helps to fill it. Not believing in luck Tanya gives the ticket to Kostya, who puts it in his book. After arrival, the paths of the compartment neighbors diverge. A few days later the newspaper publishes the results of a drawing, and it turns out that Tanya’s number wins a large sum of money. Unfortunately Kostya mixed up the copy of the book in which he had left the lucky ticket...