In New York City, a pair of narcotics detectives, Jimmy "Popeye" Doyle and his partner Buddy Russo, are on the trail of a major heroin smuggling operation. Known for their unconventional methods and tenacity, the detectives become obsessed with the case after a tip-off about a drug shipment coming from France. Their investigation leads them to a suave Frenchman, the mastermind behind the operation. The detectives navigate the gritty streets of Brooklyn and the complexities of international crime, determined to crack the case and make a significant bust.

As the detectives delve deeper, they find themselves entangled in a high-stakes game of cat and mouse. Their commitment to the case takes a toll on their personal lives and puts them in the crosshairs of the criminals they are pursuing. The operation's scale and the cunning of the opposition test their limits, pushing them to the edge of legality and morality. Amidst stakeouts, chases, and confrontations, the gritty reality of their work becomes apparent, showcasing the relentless pursuit of justice in the face of overwhelming odds.