The year 1900 ushers in a new century and the promise of social change, and women rise together toward equality. Yet rules and restrictions remain, especially for women like Alice Butterworth, whose husband has abruptly disappeared. Desperate to make a living for herself and the child she carries, Alice leaves Chicago far behind, offering sewing lessons at a New Orleans orphanage.

Constance Halstead, a young widow, has thrown herself into charitable work. Meeting Alice at the orphanage, she offers lodging in exchange for Alice's help creating a gown for the Leap Year ball of Les Mystérieuses, the first all-female krewe of Mardi Gras. During Leap Years, women have the rare opportunity to take control in their interactions with men, and upend social convention. Piece by piece, the breathtaking gown takes shape, becoming a symbol of strength for both women.

But Constance carries a burden that makes it impossible to feel truly free. Her husband, Benton, whose death remains a dangerous mystery, was deep in debt to the Black Hand, the vicious gangsters who controlled New Orleans's notorious Storyville district. Benton's death has not satisfied them. And as the Mardi Gras festivities reach their fruition, a secret emerges that will cement the bond between Alice and Constance even as it threatens the lives they're building . . .