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. Avery is questioned by Internal Affairs about the integrity of his department.

A doctor is found dead in the pool of a wellness clinic. Riggs suspects a drug angle and asks Agent Palmer for help.

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. Riggs learns the responsibilities that come with being in a relationship with help from Murtaugh.

Murtaugh and Riggs respond to a robbery that takes 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. Murtaugh faces hostility from his daughter 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. Murtaugh updates his will. 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. 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. 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. 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. Murtaugh learns that Riana is secretly dating his neighbor and nemesis' son. Riggs spends more time with his childhood friend. Scorsese's real name is revealed.

Riggs and Murtaugh are drawn into a fatal world of conspiracy theories. Riggs' relationship with Molly evolves. Murtaugh and Trish attempt to get Harper into a fancy pre-school.

It's Christmas time and the Murtaugh family is headed to Hawaii. Murtaugh's vacation is put on hold when he and Riggs are called to a homicide and the victim is an old friend. 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. Riggs decides to pay a visit to someone from his past.

Riggs takes a trip down memory lane while visiting his father-in-law in prison, which reminds him about an old secret regarding his deceased wife.

Murtaugh and Riggs respond to the murder of an escaped patient of Dr. Cahill's who mysteriously goes off the rails. Riggs' anger gets the better of him once again, causing Avery to consider whether or not he is fit to serve. Family tension runs high between Murtaugh and Trish, who have to make big decisions about R.J.

Bailey's sister runs into trouble with the law, and she must decide how far she'll go to protect her family. Murtaugh must help Riana navigate boy problems. Riggs deals with the fallout of a night of heavy drinking.

Murtaugh and Riggs search for the culprit of a local jewelry heist. Murtaugh gets called 'grandpa' by another parent while at the playground with Harper, sending him into a tizzy. 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. Murtaugh walks on thin ice with Trish. Riggs finds an unlikely friend in Ruthie. 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. 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. 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. Riggs struggles to find a connection with his father. Murtaugh scares Riana with his overprotective driving lessons. The team members 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. Riggs comes face to face with someone from his past. 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. 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 Rigg's father. 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. Trish gets caught up in some trouble. Molly asks Riggs to make a big decision about their future.

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. Trish worries about Murtaugh's health.

Riggs and Murtaugh's investigation of a drug cartel reunites Murtaugh with his former T.O. Riggs avoids the reality of Miranda's death by diverting himself with outside vices. Murtaugh and Trish struggle to find alone time.

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. 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.

The investigation of a young model's murder leads Riggs and Murtaugh to one of L.A.'s wealthiest families and Riggs is jolted when an old friend of his wife's is also linked to the case. Murtaugh is shocked to discover that his daughter is sending racy 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. With Trish and the kids away, Murtaugh goes on a 'bender'. 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.

After investigating the murder of a millennial 'designer drug' dealer, Riggs and Murtaugh find themselves in a violent turf war between a new generation of drug dealers and a Koreatown gang. Murtaugh finds some comfort in a temporary new partner. Trish attempts to set up Riggs with her co-worker.

Murtaugh and Riggs suspect misuse of power in the LA Sheriff's department when they investigate the killing of a Texas Ranger.

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. 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 Murtaugh.

Riggs and Murtaugh examine a series of violent crimes with one thing in common—the victims are all members of the same church. Riggs faces a moral dilemma when the one-year anniversary of Miranda's death sends him to a new low. 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. After finding Murtaugh's file in Cahill's office, Riggs becomes obsessed with finding out about his. 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. Riggs begins to view Agent Palmer in a new light. Murtaugh is left worried after Trish makes a spontaneous decision.

A murder involving a high school football phenomenon draws Riggs and Murtaugh into the lucrative—and corrupt—world of college recruiting. Murtaugh considers a big change in his professional life. Riggs contemplates an even bigger shift in his personal life as he spends more time with Karen Palmer.

Riggs and Murtaugh team up again with Palmer, and together they gain inside knowledge of dangerous new cartel operations. As Riggs’ attachment to Palmer deepens, so do his impulsive actions, further worrying Avery and Delgado. Trish explores the potential of an amazing new career opportunity.

Riggs makes a shocking discovery about Miranda’s death that leads him back to the cartel in a frantic search for answers. His wild desperation leaves Murtaugh torn between his commitment to his partner and his commitment to his family.