Who polices the police? Dominik Moll’s character-driven thriller introduces us to Stéphanie (Léa Drucker), a dedicated member of the IGPN—France’s internal affairs unit—who will stop at nothing to find the cops who severely injured an innocent young man during a peaceful protest in Paris. Premiering in the Cannes Film Festival’s prestigious Competition slate, Case 137 unfolds like a crack procedural as Stéphanie meticulously tracks down the flics in question, but this is no simple whodunit. Instead, Moll employs the genre to explore a stalwart officer’s gradual realization of the limitations of her job. Accused of being a traitor by her fellow cops and verbally abused by the victim’s family members, who are impatient for justice, Stéphanie must navigate an emotional minefield. Drucker’s subtle, reserved performance captures the character’s resilience and growing doubt. Case 137 is refreshingly human, measuring the toll on those devoted few trying to make a difference.