Catalina, a humble Madrilenian girl who steals fish in the company of two rogue friends, receives a strange proposal: to pass herself off as Silvia, the daughter of a South American diplomat, who has run off with a bullfighter. It will not be easy to convince her, much less convert her into a refined and elegant young woman. Despite all the efforts, things get more complicated than they thought and Silvia's father, don Fulgencio Ferreira, demands immediate news from his daughter.