Act I In the 18th century in
New Orleans'
Place d'Armes, vendors are hawking their wares ("Clear Away!"). They believe the fountain is haunted by the ghost of a woman who was killed by the pirate Bras Pique. Étienne Grandet, the son of the territory's lieutenant governor, is secretly the pirate and has been attacking ships bound for New Orleans. Étienne's father shares in his profits, and his
quadroon slave mistress Adah knows Étienne's secret. Captain Dick Warrington and Sir Harry Blake lead a band of locals into the square vowing to capture Bras Pique ("Tramp, Tramp, Tramp"). Lieutenant Governor Grandet holds them off to assist Étienne's scheme to establish a breakaway Louisiana dictatorship under his own command. Captain Dick's men are also excited about the arrival of marriageable
casquette girls that the King of France has sent ("Taisez-Vous"). Plain-looking Lizette latches on to the boastful Simon O'Hara, Captain Dick's Jewish servant. When the square clears, a fragment of the ghost's song comes from the fountain ("Mysterious Melody"). The singer is actually "Naughty Marietta", a casquette girl who escaped from her ship. Captain Dick, who had met her in
Mozambique, agrees to hide her at the
marionette theatre, where she poses as the son of the puppeteer Rudolfo. The captain insists he cannot love Marietta ("It Never, Never Can Be Love"). Marietta tells him that she will love the man who can complete the melodic fragment she dreamed up. Dick refuses her request to complete it but finds himself whistling it later. Simon tries to impress Lizette ("If I Were Anyone Else but Me"). Worried that Étienne does not love her, Adah tries to divine her future ("'Neath a Southern Moon"). Marietta performs at Rudolfo's theatre ("
Italian Street Song"). The King offers a reward for the return of the missing Contessa d'Altena, who hid among the casquette girls. She is known to sing a tune that the townfolk recognize as the ghost melody. Blake accidentally ruins Marietta's disguise. She insists she is not the Contessa and, during a scuffle between Étienne's and Dick's men, runs away with Rudolfo.
Act II Marietta learns Rudolfo's craft ("Dance of the Marionettes"). Étienne believes she is the Contessa and woos her ("You Marry a Marionette"); a marriage to a contessa would legitimize his plan for a Louisiana. The decadence of New Orleans is displayed at a quadroon ball ("New Orleans, Jeunesse Dorèe" and "The Loves of New Orleans"). Lizette pines for a husband ("The Sweet By-and-By"). Simon hopes to complete the Contessa's song and marry her, and he ignores Lizette. Marietta is shocked by the ball's immorality: drinking, gambling and womanizing. Captain Dick arrives to protect her, but thinks he has been flirting with Adah, and so she dances with Étienne ("Live for Today"), who proposes to her. She asks Étienne about Adah, and he says he will auction her. Marietta seeks out Dick, who realizes his feelings for her ("I'm Falling in Love with Someone"). Étienne auctions Adah, and Dick buys her. Marietta jealously agrees to marry Étienne and reveals she is Contessa d'Altena. Dick sets Adah free, and she offers to help him reveal Étienne as Bras Pique. Simon revels in the ease of his new job as the Grandet's
whipping boy ("It's Pretty Soft for Simon"), but when Dick fingers Étienne as Bras Pique, Simon is obligated to take the punishment. Adah tells Marietta of Étienne's pirate identity, and so she refuses to marry him. When the lieutenant governor locks her up, she hears a voice outside completing her dream song ("Ah, Sweet Mystery of Life"). It is Dick, whose men are not far behind. Dick and Marietta sing the finished song together. Étienne relinquishes his claim on Marietta, and Dick allows the pirates to escape without harm. ==Musical numbers==