Janet Hamilton (Suzanne Pleshette), a tough police captain with an impeccable reputation, is transferred to “The Sewer,” a crime-infested inner city precinct, and charged with the task of cleaning it up by the Chief of Police (Danny Aiello). She gets little support from her own men, many of whom have been thriving, in this lawless wasteland.
Sergeant Alan Benson is mysteriously shot while on duty; there seems to be no obvious motive for the crime and no clues. Upon investigation, Captain Hamilton learns that Benson was the head of a prostitution and burglary ring. The best lead is Benson’s girlfriend and accomplice, a prostitute named Wendy Prentiss (Patty Owen). Captain Hamilton tracks her down only to discover that Wendy has had her throat slit.
This brutal murder leaves a lot of people running scared, including Paige O’Brien (Charlotte D’Amboise), Wendy’s best friend, who is now worried about her own safety. Paige’s boyfriend, Officer Jim Hansen (Jon Tenney) tells Hamilton of the weekly parties at which the officers divide up their spoils with the prostitutes. The Captain is a surprise guest at the next gathering, rounding up all those involved.
But who killed Sergeant Benson and Wendy Prentiss? Under intense questioning, Benson’s former partner, Lieutenant Inforzato, breaks down and admits to the killings. He believed that if Benson were left alive he would have pinned the crimes on him.
By breaking the ring and solving the murders, Captain Hamilton succeeds in her drive against corruption and returns her precinct to respectability.