Jack Traven is an LAPD cop on SWAT detail. He has a fearless nature and a keen understanding of the criminal mind, but he is also rather reckless. Together with partner Harry, they rescue a dozen hostages from a booby-trapped elevator rigged by a psychotic ex-cop (Dennis Hopper). The bomber then makes alternative arrangements and rigs a city bus to explode if the speedometer drops below 50 mph. It’s then up to Jack to save the passengers.