A seemingly routine murder investigation by the LAPD Robbery-Homicide Division is interrupted by the arrival of Deputy Chief Brenda Johnson, the new head of the LAPD’s Priority Murder Squad. An outsider from Atlanta in her first week of service, Brenda has already begun to face the resistance of long-time high-ranking officers, particularly Capt. Taylor of Robbery Homicide, as well as the questionable confidence of her own squad, who have decided to request transfers en masse. Only her assistant, Sgt. Gabriel, seems willing to try to work with her.

Brenda and the team must investigate the murder of high-profile model Heather Kingsley, who dies as a result of nicotine poisoning, applied to her scalp via her hair conditioner. Suspicion quickly falls on her movie-star husband, Dean, whose philandering ways and false claims of a pre-nuptual agreement make him the likely killer. As Brenda investigates, she is drawn into the world of celebrity beauty, where illusion is everything, and the standard high. When she undergoes a make-over to meet the Dean’s discarded lovers one-by-one, each of whom appears to have a motive to murder, Brenda realizes there may be more to this case than a man trying to get out of a marriage. At the same time, she is slowly seduced by the superficial glamour, which seems to impress her colleagues, and Fritz. As the real killer emerges, Brenda comes to the realization that she can only be who she is, and that the rest is just an illusion.

Brenda must fight for justice for two Russian prostitutes murdered by the illegitimate son of a Russian mafia figure whiles she overcomes the prejudices of a department who sees one dead prostitute as pretty much the same as another. As she does, she confronts her own prejudices, and discovers the justice for these women is scarce in a world dominated by men. When the FBI steps in to take over the investigation, she shows the stern stuff she's made of, using highly unorthodox methods to finally bring the murderer to an unusual form of justice. Meanwhile, Brenda's relationship with Fritz takes a new direction, as the FBI's involvement in this case hints at the challenges that will come when they must balance their work and professional lives. At the end of the episode, Brenda purchases one of the dead girl's house, and finds herself the owner of a cat she doesn't want, but who has ideas of its own.

Brenda and the Priority Homicide Team investigate a sniper who is killing gang members in and around MacArthur Park. Offering assistance is an ex-Army colonel who believes the sniper to be his son. As an all-out gang war looms, Brenda tentatively accepts his assistance, but as her investigation progresses, Brenda's doubts about the Colonel's motives grow. With Fritz' assistance, she realizes the Colonel is not there to help, but to help his son escape. The two face off in the dark on a Los Angeles rooftop, leading to an unexpected outcome. Elsewhere in the story, Sanchez' prior service with the Rampart Division CRASH gang squad allows him to play a pivotal role in the investigation as he briefs the squad on gang activity in the area, goes undercover as a gang member and assists with interrogations. Brenda's tense relationship with Taylor seems to relax, then abruptly grows tenser when a stake-out goes wrong. Gabriel becomes increasingly loyal to her, but Flynn and Provenza continue to resist her methods, dubbing her "Miss Scarlett."

Brenda enters the high-stakes world of pharmaceutical research, when a drug trial for new anti-addiction medication lead to the death of one of the principal investigators. Nothing is quite as it seems as she investigates the high-powered president of the drug company sponsoring the trial, the seemingly easy-going psychiatrist and the teenaged participants in the study. Too soon, one of the teenagers falls victim to manipulation of the medication, and Brenda untangles a web of exploitation of the young victims leading to an unlikely criminal. Meanwhile, Flynn ratchets up his efforts to undermine Brenda's authority, first by going over her head to Pope, and then, when that fails, by unearthing a groundless ethics investigation Brenda faced in Atlanta. On the personal front, Brenda's relationship with Fritz heats up, much to Provenza's delight!

Brenda finds herself the unexpected victim of violence against women when she investigates the murder of a congresswoman's daughter. At first, it appears the victim was engaged in sexual activity online that included an invitation to violence. But as Brenda and the team investigate the world of online solicitation of sex, they discover just how vulnerable to abuse women are, and how easily the web can be used for revenge. In the end, Brenda finds a killer bent on revenge, and saves the victim's reputation, but not without paying a terrible price herself.

When a judge is murdered in Griffith Park, Brenda's investigation takes an unexpected twist. Her best witness, or perhaps her prime suspect, is his teenaged son with autism. Challenged by the boy's behaviors, but convinced he has the clue to unraveling the case, Brenda must try to understand his disability, and thereby learn what he knows. Meanwhile, she must keep his mother, and the child protective system from taking custody of the boy, limiting her access to him, and the killer.

When a gay man is murdered, seemingly the latest victim of a string of hate crimes, Brenda must confront prejudices inside and out of the LAPD. But when the perpetrator of the crimes turns out to be something quite different than expected, and has an alibi for the latest murder, Brenda must dig deeper to discover if this crime is part of the string, or a crime of passion disguised as a hate crime. Meanwhile, Flynn and Taylor step up their efforts to undermine Brenda once again, but with unexpected effects, as the team begins to rally around Brenda. Provenza's quirks begin to emerge, and we meet Terrence Hynes, a County Coroner's Forensics Support worker with an odd sense of humor. On the home front, Brenda finds herself with some new charges when her (male) Kitty has kittens.

The murder of an adolescent girl from Mexico, found dead in the Los Angeles River, proves difficult and painful for Brenda and her team. At first, a known sex-offender seems the likely candidate, but questions arise about why the girl and her mother were brought to the US, leading the investigation in another direction. Soon, the girl's backpack suggests the girl's uncle or the family for whom the mother worked may have been involved, A search of the house suggests one of the family is the murderer, but which one? An end-run by the family, determined to protect the killer, takes Brenda to Mexico, where she must use all her resources, Fritz and Mexican law to finally bring the killer to justice. The usually cantankerous Dr. Crippen shows his softer side as he briefs Brenda following the autopsy, in a scene representative of the way in which the violent death of a child impacts the police.

Three wealthy, spoiled and unruly children become the target of Brenda's investigation when their stepmother is murdered and the family butler seemingly commits suicide shortly thereafter. Riding heard on the trio is their family attorney, who cleans up their messes and provides them with alibis. Convinced the butler was actually murdered, Brenda sets out to discover which of the children committed the murders, and finds the real killer was someone altogether different!

Brenda finds herself at odds with the FBI in a struggle to gain control of the murder investigation of a well-known businessman. Deciding to work in tandem, Brenda finds herself working directly with Fritz, who was assigned to the case. After discovering that the FBI has ulterior motives in the investigation, Brenda's relationship with Fritz is put under further strain.

Brenda and her team must find not only a killer, but also identify the killer's victim when a deranged, homicidal madman is set free due to mistaken identity. Trying to make sense of an array of complexities in this unusual case, Brenda comes across what may be another betrayal by a member of the Priority Homicide Division. The case takes an even darker turn when Brenda becomes the center of the psychopathic killer's attention.

An unnamed source files a grievance against Brenda in the midst of a high-profile investigation of a murdered L.A. filmmaker. With her career on the line, Brenda is skeptical of Chief Pope's intentions when he volunteers to help. In classic Brenda style, she spurns the accusation, refusing to suppress her demeanor in deference to the complaint. In response to the situation, the PHD team comes together to act in unison, sending shock waves through the entire department.

Things don't add up when an LA cop turns up dead. Brenda and her team race against the clock to get to the truth, while tension increases between the Priority Homicide Division and the Robbery-Homicide Division. In the meantime, Brenda's relationship with Fritz elevates to a whole new level.

When a juror in the trial of an infamous mobster is found dead, Brenda and the Priority Homicide Division find that their involvement in solving the case may be affecting the jury's final decision. Complicating her personal life, Brenda faces another new challenge: a surprise visit from her mother.

Things are not as they seem when Brenda and the team investigate the accidental murders of three college students caught in the middle of a gang shootout. Brenda must also continue her attempts at keeping her relationship with Fritz under wraps while her mother remains in town.

Brenda and the PHD investigate a high-profile case when a woman is brutally murdered at L.A.'s trendiest restaurant. On the home front, Brenda tries to keep a low profile as she closes in on her 40th birthday.

Brenda finds herself involved in a cover-up of her own when she helps the PHD investigate a non-priority case. Why? Because the deceased woman was found in Provenza's garage. Once again, the team finds themselves racing against the clock before the LAPD brass discovers what they're up to. Will Brenda be able to protect her team and their hard-earned trust?

Brenda and the team find themselves wading through a long list of suspects when a celebrity photographer takes a fatal fall from his hotel room balcony. Once the cause of death is determined, the motive points to a big time actor with something to hide. In the meantime, Brenda starts to feel like Fritz is behaving strangely, making her realize that superstars may not be the only ones who have secrets to keep.

When a few body parts of an "adult film" star are found in a dumpster, Brenda and the team must scramble for more pieces to solve this puzzle. Once they begin putting things together, the suspect list seems to get longer. Adding more questions to her life, Brenda also finds herself making a potentially life-altering discovery.

When the drowned bodies of a mother and daughter are found by fishermen, Brenda and the team must determine if the apparent suicides are more than that. Following a strange coil of discoveries, the most surprising revelation that surfaces is one about the killer.

When a young boy blames himself for the death of his friend, Brenda must tread lightly to get to the bottom of the case. Complicating matters is the deceased child's mother, who offers up accusations of her own.

The PHD must deal with a case of mistaken identity in order to get to the bottom of an investigation. While they're busy with the case, Brenda is involved in a different case: Pope's divorce. After being called to testify, Brenda finds that both her career and reputation are on the line.

Leaving the scene of an accident to get to a multiple homicide scene, Brenda finds herself unable to drive the streets of L.A. which she worked so hard to learn. Once she gets to the crime scene, she and the PHD are faced with another challenge: the murdered bodies are nowhere to be found. In order to solve this case, they must first search for the victims before they can hunt for the killer.

Once again, the PHD finds themselves wading through suspects in the murder of the star witness in a capital punishment case. When Estelle, Pope's angry ex-wife, spills the beans about Brenda to her team, Fritz begins to wonder how she really feels.

Brenda and Fritz have a hard time agreeing who is in charge when an informant's wife and and FBI agent are both murdered. Brenda discovers that she and the PHD must work quickly when the leading witness in the case is scheduled to testify against a powerful mobster. When the killer's identity is uncovered, the PHD finds themselves under attack; an attack that takes someone down.

Resulting from the showdown in the murder room, Brenda finds herself taking some involuntary time off. When she is asked to help a friend solve a murder that is linked to a terrorist group, Brenda works to find the killer and still keep it under wraps. Meanwhile, Commander Taylor jumps at the chance to break apart the PHD while Brenda is away.

Glad to be back with her team, Brenda focuses on finding a terrorist-linked suspect. Working with the CIA, who also wants their hands on this suspect, Brenda realizes that she was given false information, and wonders if she's been set up. To prevent herself and the PHD from falling prey to a sinister plan, Brenda must untangle a web of lies to determine who she can trust - before it's too late.