New York, 1988: A new breed of narcotics has swept the great city, bringing with it a ferocious crime wave more terrifying than any in recent memory. Outmanned and outgunned by the new criminal order, the police find themselves burying one of their own at the rate of two a month. An all-out war rages, threatening to engulf guilty and innocent alike.

Bobby Green (Joaquin Phoenix) is caught in the crossfire. Manager of a Russian nightclub in Brighton Beach frequented by gangsters like Vadim Nezhinski (Alex Veadov), Bobby keeps his distance, not wanting to get involved. Despite his hedonistic, amoral lifestyle, he is committed to his girlfriend Amada (Eva Mendes) and has ambitions to open his own club and expand out of Brooklyn.

Bobby has a secret, however, which he guards closely. His brother is Police Lieutenant Joseph Grusinsky (Mark Wahlberg), who has followed in the footsteps of their father, legendary Deputy Chief Burt Grusinsky (Robert Duvall). Bobby's already strained relationship with his father and brother is tested when Burt warns his son that this is a war, and he's going to have to choose a side.

He can no longer remain neutral when his brother is badly wounded in an assassination attempt, and Bobby discovers his father could be next. Realizing they will only be safe when Nezhinski and his organization are destroyed, Bobby and Joseph join forces for an all-out assault. Together, they'll try to prove the NYPD's '80s rallying cry in the war on drugs: We Own the Night.