A woman, accidentally caught in a dark deal, turns the tables on her captors and transforms into a merciless warrior evolved beyond human logic.

William Friedkin's gritty police drama portrays two tough New York City cops trying to intercept a huge heroin shipment coming from France. An interesting contrast is established between 'Popeye' Doyle, a short-tempered alcoholic bigot who is nevertheless a hard-working and dedicated police officer, and his nemesis Alain Charnier, a suave and urbane gentleman who is nevertheless a criminal and one of the largest drug suppliers of pure heroin to North America. During the surveillance and eventual bust, Friedkin provides one of the most gripping and memorable car chase sequences ever filmed.