Set in New Orleans in 1803–1804, just as France cedes the Louisiana territory to the United States, the novel follows the intersecting lives of two feuding Creole families, the powerful Grandissimes and the dwindling De Grapions, against a backdrop of racial caste, slavery, and political upheaval.
The story opens at a masked ball in the Théâtre St. Philippe, where Agricola Fusilier, the elderly patriarch of the Grandissime-Fusilier clan, denounces the cession as fraudulent. Four maskers attract attention: a Dragoon, an Indian Queen, a small Monk, and a Huguenotte Girl dressed as a
fille à la cassette, one of the French women shipped to the colony as brides. The Dragoon is Honoré Grandissime, the family's young, pragmatic head. The Monk is Aurora Nancanou, a beautiful Creole widow, and the Huguenotte is her daughter, Clotilde Nancanou. When Honoré and Aurora unmask to each other, she recognizes him as a Grandissime and flees, leaving him dazzled but ignorant of her identity.
Joseph Frowenfeld, a young German-American immigrant, arrives in New Orleans with his parents and two sisters. Within days, the entire family except Joseph falls victim to yellow fever and dies. Doctor Charlie Keene, a small, sharp-witted physician, saves Joseph's life and becomes his first friend. Keene introduces him to Creole society and tells him about two extraordinary women living next door: Aurora and Clotilde, the last of the De Grapion line.
The novel traces the families' rivalry to 1699, when Epaminondas Fusilier won a dice throw for the hand of Lufki-Humma, a Natchez-Tchoupitoulas Indian queen, founding the Fusilier branch. The Grandissimes multiplied through Zephyr Grandissime into a vast clan, while the De Grapions dwindled to a single heir each generation. By the novel's present, the feud has a specific grievance: Aurora's husband was killed in a duel by Agricola after a gambling dispute, and Agricola seized the Nancanou plantation at Fausse Rivière. Aurora refused to sign a statement exonerating Agricola and surrendered the property. She and Clotilde now live in genteel poverty, struggling to pay rent.
While visiting his family's graves, Frowenfeld meets a sympathetic Creole gentleman who advises him to acclimate to Louisiana. They part without exchanging names. Frowenfeld opens an apothecary shop on the rue Royale and discovers that his landlord, though he signs as Honoré Grandissime, is not the Creole from the graveyard but a different man: Honoré Grandissime, free man of color (f.m.c.), the white Honoré's elder half-brother. In Louisiana's racial hierarchy, people of mixed African and European ancestry, known as quadroons, were legally free but socially confined. The f.m.c.'s father, Numa Grandissime, abandoned his mother under family pressure. Despite his wealth and education, the f.m.c. lives a shadow existence and confesses to Frowenfeld that he has loved Palmyre Philosophe for nine years without reciprocation.
Palmyre, a quadroon woman of fierce beauty and powerful will, was Aurora's enslaved childhood companion, later freed. She has become a hairdresser and practitioner of
voudou. Her heart belongs hopelessly to the white Honoré, and she harbors a consuming hatred of Agricola. When Aurora secretly visits Palmyre seeking a charm, Palmyre perceives that Aurora truly desires love rather than money and works a spell while resolving to discover the object of Aurora's affection.
That evening, Aurora is knocked down by a horse on the Place d'Armes. Honoré rides beside her, having scandalized the Creole community by appearing publicly with the new American governor, Claiborne. Frowenfeld escorts Aurora home and meets Clotilde for the first time. Later that night, Agricola is stabbed by an unknown assailant, though the wound proves minor.
The novel's central embedded narrative concerns Bras-Coupé, an African prince enslaved and brought to Louisiana. Purchased for Don José Martinez's plantation, he refuses to work. Palmyre, sent as interpreter, becomes the object of his love, though she does not reciprocate. He agrees to serve as foreman in exchange for her hand. At the wedding, he drinks wine for the first time, becomes intoxicated, and strikes his master, a capital offense under the Black Code, the body of laws governing enslaved people. He escapes into the swamp and pronounces a voudou curse on the plantation. Crops fail, and Don José falls ill. Bras-Coupé is eventually recaptured and brutally punished. On his deathbed, he weeps when shown the master's infant son, lifts the curse, and dies declaring he is going to Africa. The story functions as a parable of slavery's self-destructive violence.
Honoré faces an agonizing dilemma. He holds custody of all his family's property, including the Fausse Rivière plantation that rightfully belongs to Aurora and Clotilde. Returning it would do justice but financially ruin his kinsmen; keeping it would perpetuate injustice. He has also fallen in love with Aurora, making any restitution appear as a purchase of affection. Frowenfeld urges the f.m.c. to devote his wealth to advocacy for his oppressed people, but the f.m.c. refuses, paralyzed by despair and hatred of Agricola.
Frowenfeld's reputation is destroyed when Palmyre's enslaved attendant strikes him during a medical visit, and he staggers bleeding into the street before witnesses who assume the worst. Clotilde, who happens to be in the shop when he returns, tends his wound and declares her faith in his innocence, revealing feelings she has harbored since nursing him through his fever. Honoré arranges Frowenfeld's vindication.
Honoré finally acts. He sells a Grandissime estate and surrenders the Fausse Rivière account to Aurora and Clotilde, a balance of $105,000, accompanied by a note declaring the act is done not for love of woman but in the name of justice and the fear of God. Aurora keeps this slip close to her heart. He also enters a partnership with the f.m.c. under the name Grandissime Brothers, a public acknowledgment of kinship that enrages his family. Separately, Frowenfeld persuades Agricola to write a letter of apology to his nephew Sylvestre Grandissime, averting a duel provoked by Agricola's outburst at a family gathering.
The family erupts. Agricola harangues followers against Yankee tyranny and mixed-blood partnerships, and a mob destroys Frowenfeld's shop. Frowenfeld reopens in a larger store, with Aurora and Clotilde taking apartments above. Raoul Innerarity, Honoré's young cousin and Frowenfeld's assistant, helps manage the new premises. Voudou charms begin appearing in Agricola's quarters, traced through Clemence, an enslaved cake-vendor, back to Palmyre. Clemence is caught in a steel trap near Agricola's cottage and, under threat of death, names Palmyre.
The catastrophe arrives when Agricola encounters the f.m.c. in the new shop. Agricola strikes him with his staff; the f.m.c. draws a knife and stabs him three times. The dying patriarch is carried upstairs, where, in his final conscious act, he joins Aurora's hand with Honoré's, revealing he pledged their union to Aurora's father twenty years earlier. Clemence, meanwhile, is taken into the swamp by vengeful Grandissime kinsmen. Despite Raoul's intervention and Sylvestre's tearful protest, she is told to run and shot dead.
The f.m.c. flees to Bordeaux with Palmyre, but she refuses to marry him. His drowned body is found in the harbor. Palmyre lives out her years in solitary wealth, sustained by remittances from Honoré.
The novel closes on a gentle evening at the Place d'Armes. Frowenfeld and Clotilde walk together, their love finally declared. In the drawing room upstairs, Aurora coyly resists Honoré's proposal, insisting he marries only to fulfill his uncle's deathbed wish. He declares he loves her with all his soul. She delivers a trembling refusal, bursts into tears, laughs through them, and lets him clasp her to his heart.