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.

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.

Murtaugh and Riggs investigate the mysterious death of famous singer Shaye's bodyguard. 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.

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 realise 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 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 doing charity work - and then learns it's NBA champion Scottie Pippen. Also, Riggs has nightmares that bring up scars from his past.

Riggs and Murtaugh are led into the underground mob world as they investigate a hospital murder. Meanwhile, Murtaugh learns Riana is secretly dating his neighbour and nemesis' son, Riggs spends 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 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.

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.

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.

Murtaugh and Riggs search for the culprit of a local jewellery 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 programme is robbed, the team is out for those responsible. Meanwhile, Murtaugh walks on thin ice with Trish, Riggs finds an unlikely friend in Ruthie, and Capt. Avery is reunited with a college "frenemy" who has 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, and Murtaugh gets one last chance to make it right at home.

Murtaugh and Riggs set 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, 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 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 trouble with 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 Rigg's father. Meanwhile, Riggs is left to grapple with his family and work.

The squad's on high alert after a 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.