Burdened by spring floods, malaria and yellow fever, citizens of New Orleans often turned to voodoo practitioners-African Rosalie, Sanite Dede, Bras Coupe-for protection. None was more powerful, or feared, than Doctor John or Marie Laveau. After P.I. Wyatt Thomas encounters a ghost during a hospital visit, he tells the story to his sometimes business partner, voodoo mambo Mama Mulate. She puts him in a trance and channels the ghost, soon learning a curse connects him and a long-dead French aristocrat. They are doomed to remain connected forever, unless Wyatt can return to old New Orleans and lift the curse before midnight on New Year's Eve.