Sgt. Roger Murtaugh of the LAPD is a family man on his way to retirement, but his professional life gets much more exciting when Sgt. Martin Riggs, a loose-cannon who's under psychiatric evaluation, is assigned as his partner. The unlikely pair quickly get pulled into a dangerous investigation involving a heroin kingpin and a team full of mercenaries. The sergeants are forced to use every trick in the book in order to stop the criminals after they make the mistake of kidnapping Murtaugh's teenage daughter.