Four New York City cops are dead, killed in an ambush that has the entire police department on alert and on edge. With a cop killer on the loose and so much riding on the case, Chief of Manhattan Detectives Francis Tierney, Sr. (Jon Voight) asks his son, Detective Ray Tierney (Edward Norton), to lead the investigation. Reluctantly Ray takes over the case knowing his brother Francis Tierney, Jr. (Noah Emmerich), and alongside his brother-in-law, Jimmy Egan (Colin Farrell).

On the surface, it looked like a routine drug bust gone terribly, tragically wrong. But as Ray delves deeper into the case, he realizes someone had to have tipped off the drug dealers that the cops were coming. Someone on the inside. Worse, the evidence starts to point in an unthinkable direction: to his own brother and brother-in-law.

As the questions mount, the case forces the family to choose between their loyalties to one another and their loyalties to the department.