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 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.

Cole finds himself on the rebound after Natalie's engagement, and his new romantic interest, Julie, has an unexpected connection to A.D.A. Erica, complicating things at work. Meanwhile, Murtaugh worries about the connection between the murder he's investigating and a new opportunity for Trish to serve as co-counsel on a high-profile lawsuit with Leo Getz.

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.