Sgt. Tom Sharky is working an undercover drug deal when another officer, Smiley, unexpectedly arrives. The drug dealer takes off with Sharky in pursuit. The dealer takes a woman hostage, forces his way onto a crowded city bus and shoots the bus driver as Sharky reaches the bus and kills the dealer. However, since a civilian was shot, Sharky is demoted from Narcotics to the Vice division. Joe Tipps, Sharky’s Narcotics partner, is angry that Sharky has been demoted while Smiley, who ruined the drug bust, remains in Narcotics. Friscoe, the Vice supervisor, welcomes Sharky to the squad’s basement offices and acknowledges that he ran a good “machine” of officers in Narcotics until Smiley arrived. Sharky is assigned to work with fellow Vice officers, “Arch” and “Papa,” at a rally for gubernatorial candidate Donald Hotchkins. Meanwhile, a killer named Billy Score sneaks into a mansion and murders an undercover agent and a high-priced Asian prostitute. En route to the rally, Sharky hears about the murders, but his new co-workers remind him that their current assignment is to arrest prostitutes in the park at the rally. Later, they return to Vice with several prostitutes and Sharky interviews Mabel. She is irate when Sharky tosses her into the “cage” and complains that Friscoe is treating Percy St. Claire, a pimp who handles high-priced prostitutes, with more respect. While Percy is processed, Sharky, Arch, Papa, and Friscoe look through his belongings and discover a list of seven prostitute’s names. Arch notices each name is seven letters and Sharky realizes they are telephone numbers. When Sharky requests wiretaps for the numbers, they learn that “Siakwan” is the murdered prostitute. They are given permission for wiretaps on five of the remaining numbers, but are refused one for “Dominoe.” Sharky wants a wiretap on that number too, and insists he will get help from his friend Nosh, a wiretap expert who works in Personnel. Later, they recognize Donald Hotchkins’s voice on a wiretap recording from Dominoe’s telephone. Sharky notes that the married candidate is seeing the prostitute whose number was excluded from the wiretap list by someone in the police department. Suspicious, Sharky wants continuous surveillance on Dominoe and offers to be the point person, backed up by his new “machine.” They ask Friscoe to remain silent about the surveillance operation. Sharky and Nosh sneak into Dominoe’s apartment and rig it with surveillance equipment. She returns early and they rush to the elevator, pretending to fix it as she reaches her floor. They watch from an apartment in a nearby building as Dominoe meets her friend, Tiffany, and Sharky follows the women to their dance class. As Sharky’s surveillance operation continues, he becomes increasingly attracted to the beautiful Dominoe. Later, Donald Hotchkins arrives at Dominoe’s apartment and reveals he bought a house for her. Their rendezvous is interrupted when Dominoe receives a call from a man named Victor, who orders her to have Hotchkins leave. Later, Sharky watches as Victor arrives at Dominoe’s place. She discloses that Hotchkins bought a home for her and announces she is quitting. Victor agrees to let her quit after they have sex one more time, and Sharky gets Victor’s license plate as he leaves. While Sharky continues his surveillance, the killer, Billy Score, also watches Dominoe from an apartment in the same building as Sharky. Score snorts cocaine and takes a handful of pills before going to Dominoe’s building. He rides the elevator to her floor and fires a sawed-off shotgun through the door, shooting the woman in the face. Sharky races to Dominoe’s building and hears Billy Score in the stairwell, but the killer eludes him. Later, Sharky, Arch, Papa and Nosh work with the coroner and Barrett, a forensic officer, but do not contact Homicide, fearing the case will be buried. Sharky realizes the killer watched Dominoe from his building, and a search of the killer’s apartment unearths fingerprints and drugs. Arch and Sharky go to the bar where a drug dealer named “Kitten” operates, and Sharky waits while Arch grills Kitten outside. Kitten admits that someone bought 1,000 pills recently, but refuses to reveal the buyer’s name. Arch threatens him, but the drug dealer sees Billy Score standing in the alley. Kitten knocks Arch down and runs away, but Score’s two Asian henchmen beat the drug dealer to death, disappearing before Sharky and Arch reach the body. Sharky approaches Donald Hotchkins at a fundraiser with the news of Dominoe’s death. Later, Hotchkins confronts Victor, who insists Dominoe would have destroyed his political career. Victor offers Hotchkins the choice to continue his ascent with Victor’s help or lose the election, and Hotchkins remains on board. The next day, Friscoe demands an update from Sharky’s team. Fingerprints reveal Billy Score is the killer and they can tie him to the murders of Dominoe, Siakwan, and the undercover agent. For years, Score has trafficked young girls, who are raped, drugged and sold. Friscoe gives Sharky’s team another day to work the case before turning it over to Homicide. Sharky returns to Dominoe’s apartment and is surprised when she returns. When they realize that her friend, Tiffany, was killed instead of Dominoe, Sharky insists on getting her to safety. Nosh calls to inform Sharky that the surveillance tapes are missing. Nosh has some copies at his home, but the others are missing, and they realize someone in the department cannot be trusted. Sharky takes Dominoe to his childhood home, which he recently purchased and is renovating on weekends. Dominoe is stunned that surveillance photos of herself cover a wall in Sharky’s home. He demands to know Victor’s last name, but Dominoe refuses and they argue. The next morning, they get to know each other better and make love. Meanwhile, Sharky’s former narcotics partner, Joe Tipps, declares Sharky is right about a “fink” in the department. Joe plans to speak to the district attorney, but Score’s henchman run Joe over, killing him. That night, Sharky threatens Victor at his penthouse. Victor laughs that Sharky has no evidence; the surveillance tapes are missing and Dominoe is dead. Sharky asks if Victor has spoken with Tiffany lately, and reveals that Dominoe is alive. Sharky heads for Nosh’s home, where he is attacked by Score’s two henchmen and knocked unconscious. He wakens on a boat where he is confronted by Smiley, the police department “snitch.” Smiley reveals that Joe and Nosh are both dead, and demands to know Dominoe’s location. When Sharky refuses to answer, Smiley orders the henchmen to cut off two of his fingers. Despite the pain, Sharky rams the table at Smiley, grabs his gun and shoots him, then kills the henchmen. Sharky and Dominoe appear at the rally celebrating Hotchkins’ victory, shocking the politician into silence before he is taken into police custody. At his penthouse, Victor packs to leave and gives $20,000 to Bill Score, ordering him to lay low. Score snorts more cocaine, and insists he will not be sent away by his brother after years of working together. When Victor accuses him of being a “stupid junkie,” Score shoots his brother. Sharky, Papa and Arch arrive to arrest Victor, find his body and search for Billy Score. As they track Billy Score through the building, Papa is killed. Arch and Score badly wound each other in a gunfight, but Score keeps moving. Sharky finds Score standing in front of a window, ready to shoot himself. Sharky fires first, and Score crashes through the high-rise window, plummeting to his death. Later, Sharky and Dominoe relax in the park near his home.