When a million dollar casino heist takes a deadly turn, Riggs befriends the only credible witness, an eight-year-old boy, and takes him into his care. On the flip side, Murtaugh pulls some dangerous stunts in an attempt to prove to everyone that he can be a motorcycle guy. Meanwhile, Riggs contemplates what to do with the money he received from selling his home in Texas.

After investigating the murder of a millennial "designer drug" dealer, Riggs and Murtaugh find themselves in a violent turf war between a new generation of drug dealers and a Koreatown gang. Meanwhile, Murtaugh finds some comfort in a temporary new partner, and Trish attempts to set up Riggs with her co-worker.