A veteran cop, Murtough, is partnered with a young homicidal cop, Riggs. Both having one thing in common, hating working in pairs. Now they must learn to work with one and other to stop a gang of drug smugglers. / Riggs and Murtaugh are on the trail of South African diplomats who are using their immunity to engage in criminal activities. / Martin Riggs finally meets his match in the form of Lorna Cole, a beautiful but tough policewoman. Together with Roger Murtaugh, his partner, the three attempt to expose a crooked former policeman and his huge arms racket. The crooked cop (Jack Travis) thwarts them at every turn, mainly by killing anyone who is about to talk, but Murtaugh has personal problems of his own as his family are brought into the equation./ With personal crises and age weighing in on them, LAPD officers Riggs and Murtaugh must contend with a deadly Chinese crimelord trying to get his brother out of prison.