Judge Jeanne Charmant-Killman (Isabelle Huppert) is known in the French judicial system as "the piranha," and with good reason. A powerful examining magistrate, Jeanne has recently sanctioned the arrest of CEO Michel Humeau (François Berléand), but what she does not realize is that his company's scandal has tentacles that reach into the government and its dealings with African nations. As both prosecutor and judge, she can subpoena suspects and make her own warrants. But when she goes too far, her car is apparently tampered with, she is assigned 24-hour bodyguards, her office is vandalized, and her life is turned upside down as she uncovers more corruption than she bargained for. Her husband Philippe (Robin Renucci), a lab technician living off his family's money, is feeling eclipsed by his wife's sudden fame, and only their slacker nephew Félix (Thomas Chabrol) seems to understand what she is going through. Can she trust corporate snitch Sibaud (Patrick Bruel), who delivered Humeau to her? Or Erika (Marilyne Canto), the younger judge who has mysteriously been assigned to assist her? Inspired by the experiences of Judge Eva Joly, whose seven-year investigation into fraud and bribery at the French oil company Elf Aquitaine uncovered a web of corruption that led to convictions of top executives and former foreign minister Roland Dumas, Claude Chabrol's latest film delves into unspoken class issues in French society, demonstrating what might happen when the position that Napoleon called "the most powerful man in France" is held by a woman.