A group of rogue Force Recon Marines led by disenchanted Brigadier General Francis X Hummel (Harris) seize a stockpile of deadly VX gas--armed rockets from a heavily guarded military bunker, reluctantly leaving one of their men to die in the process. The next day, Hummel and his men seize control of Alcatraz Island during a guided tour and take 81 tourists hostage in the prison cells. Hummel then threatens the Pentagon with launching the stolen rockets against the population of San Francisco unless the government pays ransom and reparations to the families of Recon Marines who died on illegal, clandestine missions under his command and whose deaths were not honored. The Pentagon and FBI develop a plan to retake the island with a Navy SEAL Team, enlisting chemical weapons specialist Dr. Stanley Goodspeed (Cage), who initially thinks he's consulting the team, but soon learns he's being recruited due to his specialisation in chemical warfare.