Deputy Police Chief Brenda Leigh Johnson (Kyra Sedgwick) is a police detective who transfers from Atlanta to Los Angeles to head up a special unit of the LAPD that handles sensitive, high-profile murder cases. Despite a tendency to step on people's toes, Johnson manages to convert even her strongest adversaries with her unique ability to get to the truth.
After a man is murdered while taking pictures of the stars from his balcony, the squad suspects the crime is somehow connected to the woman with whom he was having an affair. But their investigation is hindered by a missing murder weapon, as well as the difficult adjustment of moving into a new office.
Capt. Raydor (special guest Mary McDonnell) accompanies Brenda on an investigation involving the disappearance of a nanny working for close friends of the mayor. Meanwhile, Raydor’s real purpose in taking part in the investigation could have big career implications for Brenda.
While investigating a suspicious suicide, the squad wades into a nasty child-custody dispute between a dying man and his meth-addicted ex-wife. Meanwhile, Pope applies for the police chief job, but Brenda might have something to say about whether or not he gets it.
Provenza once again finds himself in a professionally embarrassing situation when he discovers a dead body in the condo of a flight attendant he picked up while extraditing a prisoner.
At the request of Detective Mikki Mendoza, the squad becomes involved in investigating a series of brutal murders that indicate a Mexican drug cartel may have moved into the city.
After a parole board member is viciously murdered during a panicked phone call with Sgt. Gabriel, Pope announces an overreaching plan to boost the police department’s image. His plan, however, hinges on Brenda first being able to solve the crime.
A bank robbery supposedly committed by a known gang of thieves leaves a security guard dead. It also leaves a lot of unanswered questions about the prime suspects and why this latest robbery doesn't fit their regular pattern. Meanwhile, Pope gets some news about his chances at becoming the city's police chief.
In a case that could carry national security implications, three soldiers are gunned down outside an LA club two days after returning home from duty in Afghanistan. Brenda’s investigation puts her on a collision course with Major Edward Dorset (guest star Gary Cole), a military liaison officer.
Brenda's next case has her investigating the brutal murder of an actress who was dating through an online service, unfortunately the case takes a backseat because Brenda has an interview with the mayor for the next chief of police. Brenda still has second thoughts about whether she'd like the job.
The murder of two paramedics leads the LAPD and the FBI on separate investigations on a case that could be the precursor to a major terrorist attack. But Brenda fights to remain a step ahead, even though she's forced to work with the counter-terrorism unit's Chief Tommy Delk, who happens to be one of Brenda's fellow finalists for the job of Chief of Police.
One of Brenda's detectives is ambushed on the street, and the main clue to figuring out the motive behind the attack is a garbage bag containing more than $37,500. The investigation then turns into a race to clear the detective's name over allegations of witness tampering.
Chief of Police Tommy Delk (guest star Courtney B. Vance) assigns Major Crimes a seemingly minor case involving the armed robbery of several medical marijuana dispensaries. But when one of the robberies turns into a murder, the case becomes a test of Brenda’s readiness to move up in the department.
Brenda's holiday plans change suddenly when a man is attacked by a knife-wielding assailant who is accidentally run over and killed by the police officer responding to the 911 calls. Brenda & Fritz receive a huge surprise for Christmas from Brenda's parents.
Brenda finds she has another victim and later learns that her parents have been robbed and the Christmas gifts stolen from the RV. The investigation has to continue through Christmas day.
The routine arrest of a crack addict exposes a questionable rehab facility and leads Brenda and her squad on a race to find a missing young woman. The case leads Gabriel to question Brenda’s judgment and Fritz to reveal to Brenda the some ugly truths about his past.