Deputy Chief Brenda Leigh Johnson (series star KYRA SEDGWICK) possesses an offbeat personality, a tough-as-nails approach and a track record as one of the country's leading investigators. The CIA-trained detective heads up the Priority Murder Squad (whose name she later changes to Priority Homicide Division), a special unit of the LAPD that handles sensitive, high-profile murder cases. Brenda was chosen to lead the team because she is a world-class interrogator and an expert at obtaining confessions.

Brenda investigates the unusual murder of Heather Treman (HELEN TUCKER), a high-profile model and the wife of movie star Dean Treman (BRAD ROWE). Despite having a bad sense of direction, Brenda navigates the streets of Los Angeles to track down leads, all of which, at first glance, seem to point to Dean as the culprit. Meanwhile, Brenda meets with her ex-boyfriend Fritz for a friendly dinner and gets the name of the Priority Murder Squad (PMS) changed to the Priority Homicide Division (PHD), trading in one set of initials for a set considerably more desirable.

Brenda investigates the death of a high-priced Russian call girl whose client list reveals the name of Danny Booth (DON McMANUS), an Immigration and Customs Enforcement officer and close friend of Brenda's boss, Pope. During the investigation, Brenda questions Nick Kozlov (SETH GABEL), who was the deceased woman's boyfriend and is the illegitimate son of a Russian mob boss. Although Brenda suspects either Kozlov or Booth, she halts her investigation into the former when the FBI provides an alibi for where he was on the night of the murder. She later discovers that Kozlov is a pawn in a larger FBI investigation into the Russian mob. However, instead of being thwarted, Brenda vows to probe deeper and outsmart everyone to solve the murder. Meanwhile, Brenda leaves a message for Fritz after their dinner together. She is still unsure if they are merely friends or if their relationship could be romantic.

Brenda follows the trail of a suspected sniper who is assassinating members of the East Side Catorces, one of the city's most notorious gangs. When a retired U.S. Marine Corps colonel comes forward at the first crime scene and offers detailed information about the murders, Brenda agrees to work with him secretly to avoid scaring off the suspect. But as the case unravels, she begins to think there is more to the colonel's story than he has revealed. After more killings happen, Brenda asks Fritz to help her catch the sniper.

Brenda investigates the murder of a psychiatrist who has been involved in a controversial clinical trial for a new drug to treat teen depression and anxiety. The trail leads to several possible suspects, from the psychiatrist's partner in the clinical trial to the doctors working for the research company developing the new drug, which has already caused the death of one child. As Brenda continues her investigation, she uncovers a startling connection that ultimately leads her to the murderer. Meanwhile, Brenda's squad learns that she had been charged with sexual misconduct at her last job in Atlanta. And her tentative relationship with Fritz gets complicated when they find themselves in an awkward situation involving a hidden microphone.

Brenda investigates the murder of a U.S. Congresswoman's daughter, who may have been targeted because of an online personal ad involving role-playing in a fantasy "rape" scene. As the investigation unfolds, Brenda becomes a target in a frightening incident that leaves her emotionally and physically shaken.