A team of criminals led by mastermind Peter Branson kidnaps the President of the United States and his two guests from the Middle East, a prince and a king, on San Francisco's Golden Gate Bridge, in a masterfully conceived and clockwork-timed operation. Branson and his men block off both ends of the bridge, wire it with explosives, and demand half a billion dollars and (adding insult to injury) a full pardon for themselves. Any rescue attempts will result in the detonation of the explosives, which will kill the President (and his guests) and destroy the Golden Gate Bridge.
However, Branson is an egomaniac, and he cannot resist attention from the media. So he invites the press to stay on the bridge and cover the story. Aware that the FBI will have placed agents among them, he takes the precaution of searching them and removing the armed ones. However, Hagenbach (the FBI's dour but extremely adept head agent) has an ace in the hole: a hand-picked special agent, Paul Revson, who was equipped with only a camera. Allowed to remain on the bridge, Revson sets out to foil Branson's plans and rescue the President.
With the help of a doctor and a female journalist, Revson gets a message to his superiors, suggesting various courses of action: supplying drugged food to the terrorists, placing a submarine under the bridge, and trying to neutralize the terrorists' equipment with a laser beam. He also arranges for several carefully disguised weapons and gadgets to be smuggled to him. Working on both ends, Revson, Hagenbach, and those working with them unleash their own carefully conceived plans.