Mirko Rolín, rich owner of a car factory, is bored by his dissolute life and decides to spend his holidays alone, a long way from his Prague friends. He even bets his friend Theodor that he will go a month without home comforts and without kissing a woman. He sets out on foot for Dubrovník. There he meets Vlasta, the daughter of a Prague vineyard owner who is spending her summer there. He happens to request that he stay there the night and he ends up taking a job there as chauffeur and servant. Vlasta's father has prepared a surprise for her in the form of a potential bridegroom, who is no other than Mirko's friend Theodor. He, however, is already engaged to the actress Rosa Valetti. Rosa, alias Růžena, goes to visit him in Dubrovník, posing as Vlasta's companion. Vlasta is attracted to Mirko. Rosa tells her all about the bet. Vlasta then pretends to have a liking for Theodor, just to tease Mirko. Mirko finally kisses her - and thus loses the bet.
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