Detective Riggs (Mel Gibson) tries to settle down with his pregnant girlfriend, Lorna (Rene Russo), while his partner, Murtaugh (Danny Glover), comes to grips with the marriage of his pregnant daughter, Rianne (Traci Wolfe), to fellow cop Butters (Chris Rock). But they find themselves and their families targeted by Chinese mobsters, led by Wah Sing Ku (Jet Li). Riggs, Murtaugh, Butters and private eye Getz (Joe Pesci) decide to go on the offensive before the gangsters get to their loved ones.