Belker, LaRue and Washington go undercover to investigate a garbage removal operation with suspected mafia activity. An elderly woman is raped. After the suspected rapist is let go because his Miranda rights were not read to him in Spanish, Mayo tries to get evidence that he can speak English.
Faye gets suspicious when she visits her dentist and wakes up from anesthesia with her shirt unbuttoned. Perez goes from hero to suspect after he rescues a family from a fire in which a snitch alleges that Perez orchestrated. LaRue, Washington and Belker continue to investigate a corrupt garbage removal business.
Mayo goes undercover to bust a dentist who is suspected of taking advantage of patients while putting them under. Hill and Renko must arrest a guy who just lost his family in a hit and run crash because he has outstanding warrants. Belker gets evicted. Hunter buys himself an RV.
On her first day as Assistant District Attorney, Joyce seeks out the truth behind the assault of a young black athlete by three white teens. Mayo has dinner with Chief Daniels. Belker is looking for a place to stay and Hunter offers him his newly repaired RV.
The hunt is on for the so called 'Melon Felon' who decapitates his female victims. Chief Daniels criticizes Mayo's work the morning after they had dinner together. LaRue tr's attempt to pull a prank on foul mouthed Lt. Tabor misfires.
Operation Dirty Disco sees Goldblume and Coffey posing as waiters and Gina Srignoli wearing a mic to catch Al DiPiano. Belker and Tataglia are back together and suddenly Jablonski is giving them the cold shoulder. Fay's attempts to help a welfare mother all backfire.
Calletano is in charge of the Hill when Furillo takes part in a precinct captains retreat. Hunter's stolen RV turns into a hostage situation. Garibaldi confronts Goldblume about his new relationship with Gina Srignoli.
While demonstrating, a pro-life activist accidentally sends a pregnant woman into premature labor. LaRue and Washington film a home security video but the director is aiming for a more adult audience. Jablonski has a disagreement with the Bowling Federation.
Hill refuses to work with Renko anymore after the latter hesitated the night before. Coffey and Bates clean up a bum for Davenport so she can use him as a witness. Jablonski is accused of setting fire to the BowlMor Lanes bowling alley.
Hunter buys a tank and blows Renko and Belker's undercover operation on his first outing. Several officers pose as streetwalkers and Coffey is conflicted when he has to arrest his high school football coach. Davenport reminds Furillo it's their anniversary, while Goldblume and Gina go on a double date with Garibaldi and Fay.
Goldblume heads up his own investigation into the death of Gina. Hill uses his broadcast news connections to help a homeless family. With Bates injured, Jablonski is assigned to ride with Coffey. Calletano and Hunter interview for the captain's position. Belker uncovers police corruption while working undercover at a men's clothing store. Washington and Garibaldi get nervous about the station possibly implementing random drug tests.
Garibaldi's legal efforts to quash the drug test screenings are successful. Belker's undercover investigation nets Detective Phil Dugan and Captain Joe Keenan. Hill and Renko are in charge of escorting a bear around. Furillo's drug screening comes up positive for alcohol. Goldblume attends to Gina's estate. With one captain dead and another likely to fired, Calletano sets his sights on a promotion. Jablonski leaves the hospital without his doctor's permission to return to work.
Goldblume is held hostage by the leader of a radical group. Belker gets some bad news while working undercover. Renko is given a backstage pass to see his favorite singer. Renko and LaRue bet on who can make it to work faster.
Calletano's bid to become Captain in another precinct is put in jeopardy when his predecessor has second thoughts about retirement. Norman Buntz is introduced as Calletano's replacement. Mayor Cleveland's son is picking up on drug charges. Garibaldi gets in deep with a bookmaker. Tataglia informs Belker that she might be pregnant.
LaRue and Washington try to find clues on the person responsible for assaulting Garibaldi, who remains in critical condition. Rumors abound about Hunter's new girlfriend. Major Cleveland's son remains on the loose. Furillo assembles a committee to investigate police corruption.
While undercover, Belker get trapped in a luggage compartment on a bus. Furillo grants immunity to a stolen parts dealer with information on the death of Captain Keenan, only to later regret that decision.
The final results of Furillo's corruption commission report place blame on Daniels. An angry Daniels responds by making an example of a night shift cop involved in the shooting of a promising teen and blaming Frank. A mentally unstable man is brought in for disturbing the peace while dressed up as Rambo. Buntz becomes involved in the hiring of another khaki officer.
Buntz catches a mugger who turns around and accuses him of police brutality. Washington is involved in a domestic dispute with near tragic results. Belker goes undercover as a vagrant to investigate the reason why many vagrants have fallen from high buildings recently.
Jablonski puts up his own money to catch a pair of crooks. Buntz accuses one of Calletano's men of dumping vagrants in the Hill Street Precinct. Belker gets in the middle of a family feud between two jewelry merchant brothers. Washington is discharged from the hospital.
Furillo angers Briscoe by pursuing a major drug king on a minor charge. Hill's father comes back to ask him for money. Jablonski tries to get in between a priest and a scrap metal dealer. Belker gets upset at Tataglia for being involved in a dangerous arrest while pregnant.
Buntz and Rodriguez are held hostage by a mental patient who wants revenge on Buntz for putting him away. Belker goes undercover at a dog pound. LaRue and Washington bring in a baseball player for drunk driving and find cocaine in his car trunk. Furillo is upset when he is denied mortgage insurance.
Christmas approaches, and the cops exercise for the Fireman vs Cops Olympics. Furillo and Joyce visit his family, and are rebuked for not having children. Buntz employs a "drug-sniffing" turkey. An apartment dweller believes the Blessed Virgin appears on his wall.