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 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.

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. Avery continues his campaign for city council.