Two British officers are assigned to collect information to convict Captain Kidd of piracy.

Anna Case sings a song while the Cansino family dances in the background.

Jonathan Pride is a mild-mannered dance instructor in 1820 Boston. En route to visit relatives, Jonathan is shanghaied by a band of zany pirates and forced to work as a galley boy. When the pirate vessel arrives at the port of Las Palomas, Jonathan, clad in buccaneer's garb, makes his escape. Everyone in Las Palomas, including Governor Alcalde (Frank Morgan) and fetching senorita Serafina (Steffi Duna), assumes that Jonathan is the pirate chieftain, leading to a series of typical comic-opera complications.

Carlos Delargo, the banished son of a royal princess of Mandorra, is returned to the kingdom to be tried for a murder change. However, he is freed by King Lorenzo, whom bears a remarkable resemblance to Delargo. When the king is wounded by assassins sent by Napoleon, Delargo takes over the throne at the request of the Prime Minister in a plot to thwart the traitors. He also falls in love with Princess Teresa, the king's fiancée.

Mark Fallon, with partner Kansas John Polly, tries to introduce honest gambling on the riverboats. His first success makes enemies of the crooked gamblers and of fair Angelique Dureau, whose necklace he won. Later in New Orleans, Mark befriends Angelique's father, but she still affects to despise him as his gambling career brings him wealth. Duelling, tragedy, and romantic complications follow.