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."

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.

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.

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.

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.

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.