A slightly unhinged former Navy SEAL lands a job as a police officer in Los Angeles where he's partnered with a veteran detective trying to keep maintain a low stress level in his life.
A noise complaint at a boxer's home leads Riggs and Murtaugh to a case involving illegal gun runners and Riggs becomes personally invested in the outcome when one of their targets reminds him of his late wife. Meanwhile, Trish worries about Murtaugh's health.
Riggs and Murtaugh investigate a violent case involving a drug cartel, two killings, theft, and Murtaugh's old T.O., Ned Brower, Trish and Murtaugh struggle to find time along.
A string of burglaries hits close to home for Murtaugh when one occurs in his own neighborhood, and it gets just as personal for Riggs when another break-in ends in a casualty. Meanwhile, Roger Junior connects with an old friend who might be twisted up in some criminal action of his own.
Murtaugh delves deep into the psyche of a former navy seal who is wanted for criminal activity, and draws parallels between him and his partner, Riggs, who also served in the military. Riggs' connection to the suspect threatens to interfere with the case, but it also forces him to open up to Murtaugh.
When Riggs and Murtaugh investigate a high-profile case surrounding the murder of a young model, they uncover a vicious secret behind the locked mansion gates of one of LA's wealthiest families. Riggs gets a jolt from his past when he discovers that an old friend of his wife has ties to the case. Murtaugh is shocked to hear that his daughter is sending promiscuous photos to her new boyfriend.
Riggs and Murtaugh look into the murder of one of L.A.'s fashion expeditors and discover an underground DEA operation. In other events, with Trish and the kids away, Murtaugh goes on a "bender"; and Riggs has all-too-real dreams of Miranda.
When a million dollar casino heist takes a deadly turn, Riggs befriends the only credible witness, an eight-year-old boy, and takes him into his care. Murtaugh pulls some dangerous stunts in an attempt to prove to everyone that he can be a motorcycle guy. Riggs contemplates what to do with the money he received from selling his home in Texas.
The whole precinct's holiday celebrations are cut short when they're called to examine a ruthless homicide linked to Eddie Flores (guest star Raul Casso), the deranged nephew of a notable drug lord who has a previous history with Riggs. The holiday season weighs heavily on Riggs, who flashes back to past Christmases with his former wife, Miranda. Murtaugh is also a little preoccupied with his neighbor's obnoxious holiday decorations.
Riggs and Murtaugh are caught in a turf war between a new generation of drug dealers and a Koreatown gang; Murtaugh is teamed with a temporary new partner; and Trish tries to set up Riggs with her co-worker.
Murtaugh and Riggs square off with the L.A. Sheriff's department when their investigation into the death of a Texas Ranger leads them to a possible misuse of power. The case also surfaces a dark secret from Capt. Avery's past.
When a car containing massive amounts of cocaine is stolen from an impound lot, Riggs and Murtaugh become embroiled in a notorious car theft ring. Meanwhile, Murtaugh experiences some frightening chest pains. If Riggs' driving isn't enough of a trigger, the lead defense attorney on the case is none other than the terrifyingly brilliant Trish Murtaug.
A series of violent crimes targeting members of the same church is investigated. Riggs, meanwhile, faces a moral dilemma when the one-year anniversary of Miranda's death sends him to a new low; and Trish and Roger disagree with RJ about his future.
A brutal car crash reveals that Cahill is the target of a murderous stalker, causing Riggs and Murtaugh to turn the tables and start asking her questions for a change. Meanwhile, after finding Murtaugh's file in Cahill's office, Riggs becomes obsessed with finding out about his past as Roger and Trish reel over their daughter's newfound fake ID.
Riggs and Murtaugh are forced to work with DEA agent Karen Palmer again, to protect Leo Getz, an ambulance-chasing attorney who was linked to the Cartel. As the three delve further into the case, they begin to realize that Leo may not be the only one with a target on his back. In the meantime, Riggs begins to view Agent Palmer in a new light while Murtaugh is left worried after Trish makes a spontaneous decision
A murder involving a high school football star draws Riggs and Murtaugh into the lucrative and corrupt world of college football recruiting; Murtaugh considers a change in his professional life; Riggs spends more time with Karen Palmer.
Riggs, Murtaugh and Palmer gain inside knowledge of dangerous new cartel operations, but Riggs' attachment to Palmer worries Avery and Delgado. In other events, Trish contemplates a new career opportunity.
In the season one finale, Riggs makes a shocking discovery about Miranda's death that leads him back to the cartel in a desperate search for answers.
Murtaugh follows Riggs down to Mexico, where he plans to avenge his wife's death and finish off Tito Flores once and for all. Once back in the States, they have a few people to answer to during the ongoing investigation around Flores, including Murtaugh's family. Meanwhile, Avery is questioned by Internal Affairs about the integrity of his department.
Riggs and Murtaugh respond to the death of a plastic surgeon, drawing them into a case involving an illegal drug ring run out of a wellness clinic. Things heat up when Palmer from the DEA and Riggs compete to solve the case first. Meanwhile, Trish and Murtaugh face the emotional challenges of sending their first son, RJ, off to college
Murtaugh and Riggs investigate the mysterious death of famous singer Shaye's bodyguard. Murtaugh turns to his daughter, a fan of the singer, to learn more about Shaye's background and uncover the possible suspects. Meanwhile, Riggs learns the responsibilities that come with being in a relationship with help from Murtaugh.
Murtaugh and Riggs respond to a robbery that took place 20,000 feet in the air. The investigation turns into an ongoing hunt for an unreliable father, with his daughter being their main witness. Meanwhile, Murtaugh faces hostility from his own daughter, Riana, as he tries to connect with her.
Murtaugh and Riggs investigate a death that occurs moments before the victim's bet wins a horse race. Leo Getz insists it's a homicide and aids in the investigation. Meanwhile, Murtaugh updates his will, while Riggs struggles to come to terms with his past.
Riggs is reunited with childhood friends and comes to realize they might be mixed up in the robbery-homicide case he and Murtaugh are investigating. Meanwhile, Murtaugh finds a joint stashed in his kitchen that he brings to Scorsese for testing in effort to bust one of his kids
Riggs and Murtaugh investigate the death of a surfer. Meanwhile, Murtaugh grows suspicious of Trish's new friend, with whom she's been working on a charity event - and then learns it's NBA champion Scottie Pippen. Also, Riggs has violent nightmares that bring up scars from his childhood.
Riggs and Murtaugh are led into the underground mob world as they investigate a murder in a hospital. Meanwhile, Murtaugh learns that Riana is secretly dating his neighbor and nemesis' son. Also, Riggs spends more time with his childhood friend, Molly, and Scorsese's real name is revealed.
Riggs and Murtaugh are drawn into a fatal world of conspiracy theories. Meanwhile, Riggs' relationship with Molly evolves and Murtaugh and Trish attempt to get Harper into a fancy pre-school.
It's Christmas time and the Murtaugh family is headed to Hawaii. However, Murtaugh's vacation is put on hold when he and Riggs are called to a homicide and the victim is an old friend. Meanwhile, Riggs gets a surprise phone call from a relative just in time for Christmas.
Riggs and Murtaugh are thrown into the world of counterfeit money. When a group of teenagers inadvertently gets involved, it strikes a chord with Murtaugh, who is dealing with his own issues regarding his son, RJ. Meanwhile, Riggs decides to pay a visit to someone from his past.
When Riggs visits his father-in-law in prison, a walk down memory lane reveals an old secret about his deceased wife. Meanwhile Murtaugh tries to impress Captain Avery, and, united by the death of a mutual friend, Trish and Leo Getz try and solve a murder on their own
Murtaugh and Riggs respond to the murder of an escaped patient of Dr. Cahill's who mysteriously goes off the rails. The investigation brings to light a hidden scheme far bigger than they imagined. Meanwhile, Riggs' anger gets the better of him once again, causing Avery to consider whether or not he is fit to serve. Also, family tension runs high between Murtaugh and Trish, who have to make big decisions about R.J.
When Detective Bailey's sister, Jess, runs into trouble with the law, Bailey must decide how far she's willing to go to protect her family. Meanwhile, with Trish away on a company retreat, Murtaugh is left to help Riana navigate boy problems, and Riggs deals with the fallout of a night of heavy drinking.
Murtaugh and Riggs search for the culprit of a local jewelry heist. Meanwhile, Murtaugh gets called "grandpa" by another parent while at the playground with Harper, sending him into a tizzy, and Riggs deals with withdrawal from drinking.
After the city's gun buy-back program is robbed, the team is on a hunt for those responsible. Meanwhile, Murtaugh walks on thin ice with Trish, Riggs finds an unlikely friend in Ruthie, and Captain Avery is reunited with a college "frenemy" who has key information about the case.
After the fatal end to an argument on a construction site, the squad works to untangle facts about the incident. Meanwhile, Riggs struggles to rekindle his relationship with Molly, Trish's job is on the line as she tries to close a big deal at work, and Murtaugh gets one last chance to make it right at home.
The duo sets out to unlock a case about a veteran hitman who Murtaugh has followed for years. Meanwhile, Riggs struggles to find a connection with his father, Murtaugh scares Riana with his overprotective driving lessons, and the team finds themselves wedged in a dangerous incident that tests their trust.
When Riggs and Murtaugh attend Leo Getz's surprise wedding, they end up investigating a missing person. Then, Riggs comes face to face with someone from his past and Murtaugh receives news that might change his life forever.
After a mansion break-in turns into a homicide, Murtaugh and Riggs set out to find the culprit. Murtaugh and Trish question their trust in Riana as she gets into some trouble with new friends. Meanwhile, Riggs recalls his troubling childhood and finds a true family with Molly and Ben.
On Murtaugh's first day on the job as interim captain, the wife of a popular businessman is abducted and the squad finds a connection in the case to Riggs' father. Meanwhile, Riggs is left to grapple with his family and work.
The squad is on high alert after an apparent threat is made on Riggs' life. With Murtaugh taking on more responsibility at work, he and Riggs have to deal with their changing relationship. Meanwhile, Trish gets caught up in some trouble and Molly asks Riggs to make a big decision about their future.
Former international CIA operative Wesley Cole returns home and assumes duty as a police officer with the LAPD. Cole will find himself navigating a new partnership with Murtaugh, as he adjusts to life in Los Angeles. Meanwhile, Avery continues his campaign for city council.
New partners Murtaugh and Cole attempt to find a steady rhythm as they work to solve the murder of a finance executive. Meanwhile, Cole navigates his role with his ex, Natalie, and his daughter, Maya, and Avery grapples with the outcome of his campaign for city council.
Cole juggles the realities of his job and his duty to be a good parent, as he and Murtaugh work together to bust a gang running a lottery scam. Murtaugh gets ready to celebrate his 30th anniversary with the LAPD and receives a surprise visit from his competitive father-in-law, Don Bennett.
Cole reflects upon his time working for the CIA, as a person from the past makes a startling reappearance. Murtaugh struggles with his own mistakes, after a murder raises questions about a suspect he put away years prior. Meanwhile, Leo Getz returns as the attorney on the case and tries to convince Trish to join his team.
Murtaugh and Cole investigate after a robbery of a truck filled with fine art. Cole deals with lingering feelings for Natalie after a development in her life. Meanwhile, Riana blackmails Murtaugh into letting her go to a concert after she catches him in a lie he told Trish.
Cole confronts his past when his former mentor, Tom Barnes, delivers alarming news, as he and Murtaugh investigate a robbery of safe deposit boxes. Meanwhile, Murtaugh clashes with Trish's new client, Louie Gutierrez aka "The Gute" and enlists Bailey's help to investigate her.
Murtaugh turns to Cole's former mentor, Tom Barnes, for help on a high-stakes cartel case. Meanwhile, Murtaugh and Trish meet Natalie and Maya for the first time, and tensions mount between Bailey and "The Gute", as the new partners begin to work together.
Cole wants to talk to Natalie about their relationship before it's too late, but a wrench is thrown in his plans after he bumps into a new ADA, Erica. Meanwhile, after being kicked out of the house for Trish's girl's night, Murtaugh finds himself an unlikely friend.
While Cole gets into the holiday spirit for his first Christmas with Maya, Murtaugh hopes he can convince RJ to come back home from Costa Rica for the holidays. At the precinct, Cole and Murtaugh are saddled with a complicated burglary and home invasion case. Meanwhile, Avery's holidays are a bit blue, and Bailey is still trying to figure out her new partner.
Cole finds himself on the rebound after Natalie's engagement, and his new romantic interest, Julie, has an unexpected connection to A.D.A. Erica, complicating things at work. Meanwhile, Murtaugh worries about the connection between the murder he's investigating and a new opportunity for Trish to serve as co-counsel on a high-profile lawsuit with Leo Getz.
Murtaugh takes a family vacation, but is pulled back into work when he witnesses an alleged abduction. Cole is left to investigate a murder himself, but the two cases begin to intersect. Meanwhile, Erica's mother, Senator Malick, comes to town and stirs things up between Erica, Cole and the case at hand.
Murtaugh and Cole investigate the murder of an underground MMA fighter when Murtaugh realizes his fighting moves aren't as sharp as they once were. Meanwhile, Trish is unfulfilled by her practice and considers running for a public office. Also, Cole and Erica try to keep things casual and uncomplicated but their plan backfires when Maya reacts to her family changes in a negative way.
When Cole and Murtaugh investigate a case involving a father and daughter crossing the Mexican border, they end up uncovering a major issue with California Boarder Patrol. Meanwhile, Trish prepares her campaign for D.A. and must face parts of her past, before they find their way into the media spotlight. Cole also confronts his past when he experiences flashbacks as a result of an injury.
Against Murtaugh's advice, Cole reaches out to Tom Barnes to help with a case that hits close to home, putting Murtaugh and Cole's partnership to the test. Meanwhile, Trish prepares to announce her campaign for District Attorney.
When Cole is investigated by the FBI, Murtaugh is forced to question his loyalty to his own partner. Meanwhile, Cole works a case that puts Natalie's fiancé, Andrew, into the crosshairs right before their wedding day.
