This thrilling action film offers non-stop, runaway adventure down the streets and freeways of L.A. Howard Payne is the psychotic villain who is first seen sabotaging a high-rise elevator. He will spare the passengers in exchange for cash. Enter Jack Traven and the S.W.A.T. team who in a daring rescue save the elevator and shoot Payne. Unfortunately Payne didn't die and later tells Traven his newest scheme: he has wired a Santa Monica bus, travelling during morning rush hour on the freeway, to explode if it goes under 50 mph. Jack gets on board and has to deal with a variety of panicky passengers while trying to gain control of the vehicle helmed by a wounded driver. Annie, recently arrested for speeding, replaces the driver. Now, under pressure from both passengers and headquarters, it is up to Jack to disarm the bomb. After a spectacular scene where the bus jumps a 50 foot gap in an overpass, the police guide it to the airport and disarm it. But Payne is still busy at work. His actions lead to one final, fatal face-off on a hellish subway ride.