Jeanne and Jean are a newlywed couple living in a serene rural village in medieval France. Tragically, on Jeanne's wedding night, she endures a horrific gang-rape orchestrated by the local baron and his courtiers. When she returns to her husband Jean, filled with terror, he tries to soothe her fears, suggesting they can forget the past and start anew. However, in a shocking twist, Jean strangles her into unconsciousness, overwhelmed by his own turmoil, before fleeing their home in shame and distress.
That very night, Jeanne starts experiencing eerie visions of a spirit with a phallic head who claims to offer her power. This spirit reveals that it has heard her silent plea for help and assures her that it can grow as large and formidable as she desires. Consequently, while famine grips the village and the baron increases taxes to support his war efforts, the couple's fortunes inexplicably rise. Formerly trapped in the grind of menial labor, Jean is suddenly appointed as the tax collector. Yet his fortunes take a dark turn when the baron brutally cuts off Jean’s hand, punishing him for failing to extract adequate money from the villagers, which plunges Jean into despair and drunkenness.
Jeanne encounters the spirit once again—this time, it has grown in size—and is coerced into a troubling exchange where the spirit rapes her in return for wealth. Despite relinquishing her body to the spirit, Jeanne strongly asserts that her soul still belongs to Jean and God. In a bold move, she borrows a significant sum from a usurer, immersing herself in the trade and ultimately becoming the true authority in the village. When the baron triumphantly returns from war, his wife, consumed by jealousy over the reverence Jeanne commands, accuses her of witchcraft, rallying the townsfolk against her. As chaos ensues, Jeanne desperately attempts to return to her home, only to be refused entry, leading to her brutal assault.
That night, as soldiers close in to apprehend her, Jeanne escapes into the forest. In the wilderness, she forges a pact with the spirit, who unveils himself as the Devil. This deal grants her magical abilities, and upon returning to a village now ravaged by the bubonic plague, Jeanne creates a miraculous cure for the sickness, drawing the villagers to her for assistance. Winning their loyalty, Jeanne leads them in wild rites.
In a twist of fate, a page who has fallen for the baron's wife asks Jeanne for her help to win her love. She provides him with a love potion, which results in the baron's wife succumbing to his advances. Unfortunately, when the baron discovers their affair, he murders both of them. Frustrated by Jeanne's burgeoning power, the baron sends Jean to invite her for a meeting. In an emotional reunion, the couple reconciles, and Jeanne agrees to meet with the baron. However, when he offers her the position of the second-highest noble in exchange for her cure for the plague, Jeanne boldly declines, expressing her ambition to conquer the entire world.
This refusal ignites the baron's fury, resulting in a death sentence for Jeanne, who is to be burned at the stake. Jean valiantly attempts to protect her but is slain by the baron's soldiers, inciting a riot among the villagers. As Jeanne is engulfed in flames, a haunting transformation occurs—the faces of the female villagers morph into Jeanne's likeness, fulfilling a priest's ominous prophecy: if a witch dies clinging to her pride, her soul will endure and infect those around her. Centuries later, the enduring impact of Jeanne's spirit is heralded as a catalyst for the French Revolution.
