A decorated military hero (Ed Harris) and his band of commandos seize Alcatraz Island, taking a group of tourists hostage. His demands are simple. He wants recognition, benefits and tributes for the families of covert military operatives who have died in service to their country. If his demands are not met, he will launch a battery of rockets charged with lethal poison gas into San Francisco.

The city's only hope for salvation is an FBI chemical weapons expert and a top-secret federal prisoner (Sean Connery), who is the only known convict to have escaped the island fortress. With the clock ticking, this unlikely duo embarks on a desperate bid to infiltrate the island and detoxify the weapons before disaster strikes.