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.

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.

The whole precinct’s holiday celebrations are cut short when they’re called to examine a ruthless homicide.

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.

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.

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.