A national crime syndicate has moved into the city, taking local boss Nick Scanlon (Robert Ryan) under its wing. The syndicate—led by a shadowy figure known only as "the old man"—plans on installing corrupt Assistant States Attorney Mortimer Welsh (Ray Collins) in the judiciary. One man stands in the way of their plans: notoriously on-the-level cop Tom McQuigg (Robert Mitchum), captain of the 7th precinct. Scanlon and McQuigg have a long and antagonistic history that has stalled the good cop’s career and gotten him bounced all over the city’s corrupt precincts. Only his secret backing by the Senate’s crime commission has kept McQuigg in a job. The syndicate’s plans for Mortimer teeter on the brink of collapse when Scanlon’s kid brother gets mixed up with a nightclub singer named Irene Hayes (Lizabeth Scott). When McQuigg uses Scanlon’s disapproval of the pairing as a wedge between the local thug and the syndicate, hotheaded Scanlon kills a cop and is arrested. If Scanlon turns stoolie it will destroy Welsh’s career and seriously damage the syndicate unless Detective Sergeant Turk (William Conrad), special investigator for the States Attorney’s office, can find a way to silence him.