Poison Priestess (Lady Slayers)

In 17th-century Paris, 19-year-old Catherine Monvoisin is a well-heeled jeweler's wife with a peculiar taste for the arcane. She lives a comfortable life, far removed from a childhood of abject destitution--until her kind spendthrift of a husband lands them both in debt. Hell-bent on avoiding a return to poverty, Catherine must rely on her prophetic visions and the grimoire gifted to her by a talented diviner to reinvent herself as a sorceress. With the help of the grifter Marie Bosse, Catherine divines fortunes in the IIle de la Citee--home to sorcerers and scoundrels.
There she encounters the Marquise de Montespan, a stunning noblewoman. When the Marquise becomes Louis XIV's royal mistress with Catherine's help, her ascension catapults Catherine to notoriety. Catherine takes easily to her glittering new life as the Sorceress La Voisin, pitting the depraved noblesse against one other to her advantage. The stakes soar ever higher when her path crosses with that of a young magician. A charged rivalry between sorceress and magician leads to Black Masses, tangled deceptions, and grisly murder--and sets Catherine on a collision course that threatens her own life.