Determined to secure the release of her father—imprisoned for advocating communism—Sílvia travels to Rio de Janeiro, where she finds work as a chorus girl at the Cassino da Urca. There, she meets and falls in love with a croupier named Tide. Sílvia becomes a celebrated beauty of Rio's nightlife but is blackmailed by a Nazi named Jofre; he promises to help free her father if she marries Michael, an Englishman from whom Jofre intends to steal a map to a uranium mine.