It is 1833, and as Mardi Gras draws near, carnival fever mounts in the muddy streets and glittering ballrooms of old New Orleans....
Here Benjamin January, recently returned from Paris, has found a job playing piano at the Salle d'Orleans. It is a position that allows him a unique view of the riotous goings-on, as revelers - white, black, and colored, American and French - come together to dance, drink, and dally until dawn. But on this night, at the Blue Ribbon Ball, Ben finds himself doing more than observing.
He goes to the rescue of a masked beauty, only to discover that he once knew her very well. Mademoiselle Madeleine was always a passionate child. Now grown, married, and widowed, she has apparently lost none of her intensity, for she has dared to do the unthinkable for a white woman: steal into a quadroon ball to confront her late husband's Creole mistress.
Wishing only to keep Madeleine from being discovered, Ben offers to see the infamous Angelique Crozat in her stead, to arrange a meeting between the two women. But playing knight-errant will soon land Ben in a wealth of trouble. For ravishing, poisonous Angelique Crozat is suddenly found murdered, a scarf pulled taut around her silken throat, her luscious body hidden beneath a loose tangle of opera capes.
At first the authorities seem reluctant to pursue the investigation. After all, in the eyes of the law, Angelique is still nothing more than a colored whore. Yet Ben can't let it rest. Searching for justice for Angelique, he begins his own inquiry - one that takes him through the seamy haunts of riverboatmen and into the huts of voodoo-worshipping slaves - only to find that the police are asking questions about him. Black as the slave who fathered him, Benjamin January becomes the perfect scapegoat for the prominent men of New Orleans.