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.
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.
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.
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. After being kicked out of the house for Trish's girl's night, Murtaugh finds himself an unlikely friend.
Murtaugh and Cole investigate a robbery of a truck filled with fine art. Cole deals with lingering feelings for Natalie following a new development in her life. Riana blackmails Murtaugh into letting her go to a concert after she catches him in a lie that he told Trish.
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.
New partners Murtaugh and Cole attempt to find a steady rhythm as they work to solve the murder of a finance executive. Cole navigates his role with his ex- and his daughter. Avery grapples with the outcome of his campaign for city council.
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.