Along with dealing with the cases themselves, there are sub-plots dealing with the personal lives of Williams and Torres: Williams dealing with his ex-girlfriend Chantel and visiting their son, Gregory (just usually called G), and Torres usually interacting with his father Mike, a recovering heroin addict. Many episodes feature an R&B café called Natalie's, which is just an easy way for musical guest stars to get on the show (Natalie herself being played by Gladys Knight).
By the end of the season three finale, however, McNamara and Torres (the latter married to Nina and transferring to a new precinct) are killed off. At the start of the fourth season, everything changes. Williams and Moreno transfer to New York's Special Investigations Division answering to Lt. Malcolm Barker (and ultimately writing Cooper out of the show). They also work with Det. Nell Delaney and Det. Alec Stone. Natalie's and the musical guests that appeared were written out entirely as were any living reoccurring characters from the past three seasons except for G. As a result of all these changes, ratings for the show dramatically dropped, forcing Fox to cancel the series.
There are currently talks of a reboot in the works and that it is to air on ABC. Both Malik Yoba (Williams) and Lauren Velez (Moreno) have expressed interest in reprising their roles.
This show provides examples of:
- Asshole Victim: Alphonse in "Student Affairs" is an obnoxious, disrespectful, manipulative and violent Jerkass who even beats up Torres when he tries to break up a fight between him and a rival student. Needless to say, while Principal Stubbs chides detectives for not doing more to prevent his murder, she's more angry about the damage it did to the school's image and the detectives are more upset for the student who shot him in self-defense.
- Bald of Authority: Lt. Barker in the final season.
- Best Served Cold: The episode where Internal Affairs went after J.C. for the murder of Danny Cort had a Black staffer explain that years earlier two White cops had physically and verbally harassed him while on a date and laughed over what they did. In the present day, now as someone who held both of their jobs in his hands, explains to Torres what happened to them: while one was now a night watchman at a loading dock, the other Ate His Gun after losing his job.
- Bodyguard Crush: Tammy Barrett of "The Eyewitness Blues" soon develops one on Williams, a crush that he nearly reciprocates. Unfortunately, this causes a strain on his relationship with Sandy that lasts for several episodes.
- The Boxing Episode: "Mama Said Knock You Out", where Torres investigates the overdose death of a boxer. It culminates in him almost dying of a hot dose himself by the doer if not for some very quick actions of Williams.
- Broken Pedestal: "The Friendly Neighborhood Dealer" has a retired basketball star act as a mentor and a basketball coach for children, including J.C.'s son G. It soon comes out that he was also a drug dealer who was responsible for several overdoses of young men and in killing the father of one of the men who tried to seek revenge for his actions that killed his son. By the end of the episode after learning what he truly is, G throws his autographed basketball card he personally received from him away.
- Buddy Cop Show: Notable for being the first police drama on American television to feature two people of color in the starring roles.
- Celebrity Star: The musical guests from the first three seasons.
- Come Out, Come Out, Wherever You Are: Said to an ex-con sex offender on the run by one of the cops.
- Crossover: When Nina seeks counseling for her PTSD after being shot, her therapist is none other than Elizabeth Olivet of Law & Order (which was also created by Dick Wolf), meaning the two exist in a Shared Universe. Dr. Emil Skoda showed up occasionally as well.
- Cruel and Unusual Death: Happens from time to time, but one episode had a particularly nasty example. It involved two rival motorcycle gangs and had members from one gang kill the family of one of the rival gang's members. As an act of revenge, the killers are then hanged by their arms and had a chain attached to each leg which was attached to a motorcycle. We know what happens next, even with the scene cutting to black over their agonized screams.
- Da Chief: Lt. Cooper from seasons 1-3 and Lt. Barker in season 4.
- Depraved Homosexual: The killer from "Blondes Have More Fun". He kills the episode's main victim, a beloved drag queen, and then ends up killing two more drags queens, a one-time suspect, a supposed virulently homophobic shop owner and kidnaps and tries to kill a gay investigative reporter, but not before attempting to frame him for the crime all because of his own sense of jealousy and desire for fame and attention. Once the detectives corner him on the rooftop of his studio however, he jumps to his death.
- Dirty Coward: Danny-Up's bodyguard Big Dog in "Catman Came Back". When in a gunfight with the detectives, he ran for his life and let Danny's kid brother get fatally shot even though his boss ordered him to protect him. He eventually is shot dead by Danny with a replica of J.C.'s gun.
- Dropped a Bridge on Him: Torres in the season 3 finale.
- Driven to Suicide:
- "To Protect and Serve" had a decorated police officer kill his niece's drug dealing boyfriend to protect her from the life, but he had killed the wrong man. Just as Williams and Torres, the latter who was reluctant to believe that he was involved initially, were to bring him in, he requested to use the bathroom and subsequently shoots himself.
- "Blue Boy" had a convicted child molester, who had just been released from prison, suspected in molesting another young girl. After being harassed by neighbors and his mother accidentally being killed in a drive-by shooting meant to kill him, he admits to his crime and in accepting that his beloved mother is dead because of him and that he will never be able to stop his ways, he jumps to his death.
- Drugs Are Bad: Seen plenty of times as drugs are usually a motive for many crimes. It becomes personal for Torres after his father eventually dies of a heroin overdose.
- Empathy Doll Shot: In the aforementioned episode of the motorcycle gangs, after her mother is killed, the daughter then wanders out of her room, unbeknownst to what just occurred and holding a teddy bear. The next scene is of the bear slowly falling to the ground.
- Even Evil Has Loved Ones: Many of the most vicious criminals still have loved ones that they genuinely care about.
- Danny Cort had his kid brother, a law school student and their mother, who pretty much disowned him after her younger son's death.
- Orlando Maldone, the drug lord who shot Nina in the season 2 finale, loved and doted on his young daughter, Lucia.
- Fair Cop: To varying degrees and more realistic than the model-types frequently seen on other police shows, but overall, a very good-looking collection of officers.
- Finger in the Mail: Danny Cort murdered and cut off the middle finger of a rival in the drug-dealing business and sent it to Williams.
- Five-Token Band: Season 3 had Williams (a black man), Torres (a latino man), Lt. Cooper (a white woman), Moreno (a latino woman) and McNamara (a white man).
- Flatline: This happened to Moreno in the season 2 finale and season 3 premiere. She was brought back via Magical Defibrillator.
- Frame-Up: "Sympathy For The Devil" had three Black teenagers be accused of shooting a pair of White joggers, killing the wife (who was pregnant at the time, and the baby boy she had also died a short time after his emergency c-section birth) and injuring the husband. While it appears that they were guilty, especially when the woman's necklace was found in one of the boy's possession, turns out the husband shot and killed her himself since she cheated and the baby wasn't his.
- Implacable Man: Remmy Powers, the hitman from "The Eyewitness Blues". After singer Tammy Barrett witnesses her crooked manager's murder, he tries to kill her on three different occasions, even via a sniper's shot whilst leaving said manager's funeral. He also kills his cohort in the initial murder when he tries to get them to leave town with the money they've already procured and attempts to kill Williams and Torres when they've come to arrest him. He eventually gets struck and killed by a truck for his troubles.
- The Infiltration: The team's undercover assignments.
- In the Blood: Nina's mother is also a police officer.
- It's Personal:
- Many of the cases, although the most personal case was between Williams and Danny-Up, with each man killing a loved one of the other and their rivalry stretching on between the first two seasons. One scene even had the latter kidnap Williams' ex-girlfriend and son and pulling the trigger of an empty gun against G's head just to screw with his parents.
- The hatred between Moreno and Nadine Jordan runs a close second, with the latter having murdered Torres by car bomb not even 24 hours after they finally got married.
- Knight Templar Parent: An episode had a young supermodel end up being attacked and having her face slashed up. Even though there was a variety of suspects and the motive appeared to be jealousy, it was later discovered that her overprotective father attacked her, to get her out of the business.
- Like Goes with Like: Played straight. Despite the multiracial cast, there was hardly anyone dating outside of their race. Season 4 did have Williams and Moreno briefly hook up, however.
- Local Hangout: Natalie's, which had several popular classic and 90's recording artists performing at the club and who would give a performance as the closing credits rolled.
- Malcolm Xerox: Minister Malik in the episode The Reckoning.
- Mama Bear: When Lt. Cooper finally catches up to the man who kidnapped and sexually abused her teenage daughter, she shoots him before he can run her down in his car.
- Manipulative Bitch: Simone, J.C.'s Romantic False Lead, who was little more than a pawn working for Danny Cort.
- Meaningful Name: Snake from "High on the Hog". His actions have more than earned the name: he not only machinated the death of his brother's ex-girlfriend for betraying their gang by testifying against them and his own six-year-old niece for being a witness, but he also sets up and brutally murders the hitman and finally kills his own brother when he confronts then denounces him.
- Never My Fault: In "Mate", Eddie and his sister suspect her husband is cheating on her with his secretary and upon going to his law office, catch the two of them making out red-handed. Yet, when an angry Eddie confronts his brother-in-law, he gets mad at them for invading his privacy and at Eddie for snooping around in his marriage.
- New Jack Swing: The show features some in its score and licensed tracks alongside hip hop and soul. Not surprising, since it was created by the record label that spearheaded the new jack swing movement, the now-defunct Uptown/MCA Records.
- No Social Skills: M.E. Wong, who is usually brusque and insensitive whenever he appears. The detectives would take it in stride until Sandy's murder, where he referred to her as the body and offhandedly asks why J.C. was in his robe, which earned him a shut up from Eddie.
- Nothing but Hits: Many, many of the music played throughout the show and even the musical guest star of the episode performing at Natalie's.
- Outliving One's Offspring:
- Lt. Cooper's eldest son died of leukemia at the age of eight.
- Detective Williams outlives his and Sandy's unborn child after they were both murdered.
- Ripped from the Headlines: A given for a show created by Dick Wolf. Some notable cases included the JonBenet Ramsey case and the murder of Tupac Shakur.
- The Rival:
- Williams and Danny Cort, oh so much and for very good reasons: Williams killed Danny's kid brother in self-defense and Danny killed Williams' pregnant fiancée to even the score.
- Moreno and Nadine Jordan for pretty much the same: Torres, along with Williams, fatally wounded Jordan's husband during a shootout after a failed bank robbery. In retaliation, Jordan executed Torres via car bomb, less than 24 hours after he and Moreno tied the knot.
- Say My Name: Done by J.C. on two separate occasions, right before someone he cares about gets the ax.
- "Catman Comes Back": Upon learning that Danny Cort was on the loose and seeking revenge for J.C. having shot his younger brother, J.C. cries out his fiancé's name. He could not save her, even as he was two rooms away, since Danny was literally knocking on their door by that point.
- The aptly named "The Last Hurrah" has the female mastermind of a bank robbery ring out for blood after Eddie and J.C. mortally wound her boyfriend in a shootout. At the end, she calls J.C. to let him he's next on her hit list just as Eddie is about to drive off. J.C. has just enough time to yell Eddie's name before losing his partner of three seasons to External Combustion.
- Shoo Out the New Guy: Tommy McNamara was added onto the show
by the network as they felt that they needed a White Male Lead to bring in more viewers of a wider demographic. Neither fans nor the crew ever warmed up to his addition and he was gone a season later. - Teaser-Only Character: Most of the characters that are killed during the teaser.
- Teen Pregnancy: J.C. and his former girlfriend Chantal had their son, G, when they were teenagers. The same thing happened to Nina and her daughter, only she was forced to give her up by her mother.
- True Companions: All of them, specifically J.C. and Eddie.
- Undercover Model: In a change of pace, it was one of the guys who was a model, not Moreno.
- The 'Verse: The show is set in the Law & Order continuity thanks to both shows sharing the same psychologists.
- Vigilante Execution: Played straight with J.C. killing Danny Cort, averted with Eddie, who had the man who shot Nina cornered, but shot away from him at the last moment.
- Vigilante Injustice: A black man takes his sick daughter to a hospital and demands that she be treated by a white doctor, believing that black doctors are less competent. After some time, the white doctor comes out and tells him that his daughter is going to be fine. Sometime later, a black doctor comes out and informs him that she has died due to complications. The father is enraged, believing that it was the black doctor's fault. At the end of the episode, he is found having just murdered the black doctor with an injection and is informed that his daughter's death was actually the fault of the white doctor, who as it turns out, had a habit of drinking before going on shift and consequently distributing potentially lethal doses of medication to his patients due to his inebriated state. Thankfully, the detectives are able to get some measure of actual justice for the little girl and her torn-apart family by catching the doctor in the act of attempting to work on patients while inebriated after luring him into a trap, resulting in his arrest.
- Villain Has a Point: During their gun fight, Danny Cort tells J.C. that he couldn't leave well alone, culminating in them to the point of trying to kill the other one. As big as a scumbag and an asshole he is, he was right. Had he not been so hard up to nail him (which even Lt. Cooper even said to put off going after him to focus on his wedding in two days), then neither Danny's brother nor his pregnant fiancée would have been killed.
- Visit by Divorced Dad: J.C. and G's relationship.
- Would Hurt a Child: Danny Cort on more than one occasion. Aside from killing Williams' unborn child with Sandy after he kills her and holding up G at gunpoint, he also gets so angry at one of his drug dealer's kid brother for partaking in his product, that he punches the already intoxicated boy out cold.
- Yank the Dog's Chain: "The Highest Bidder" has Chantal, who works as a maternity nurse at a hospital with numerous budget cuts, help to solve a kidnapping of one of the newborns and the murder of his mother. Whereas it initially looks like she will be somehow rewarded for her efforts, she is nonetheless laid off at the end of the episode.
- You Should Have Died Instead: Danny Cort's mother felt this way about her elder son before and after his younger brother was murdered (as it was him who brought his brother into the world of drug dealing in the first place).
