 A Boeing 747, Oceanic Airlines flight 343, has just taken off from Athens, Greece, and is headed for the USA. Minutes after takeoff, the airplane is taken hostage by a group of terrorists led by Nagi Hassan. One of the hostages is a United States senator named Mavros. Hassan is demanding the release of one of his comrades, Elsai ad Jaffa, who is being held by United States authorities. Lieutenant Colonel Austin Travis is the leader of a military team. As the jet approaches the USA, engineer Dennis Cahill designs a plan in which a military plane will be able to transfer Austin and his team onto the 747 in mid air. Also along for the mission will be Dennis and intelligence agent David Grant. When Austin is killed in the process of boarding the 747, David is forced to take over the rescue attempt, and after boarding the airplane, David and the military team discover that Hassan has some stolen Soviet nerve gas attached to a bomb, and he is using the 747 to smuggle the deadly gas into the United States, where he intends to use it to wipe out Washington D.C. and possibly the entire Eastern seaboard. It s up to Dennis to defuse the bomb while David and the team try to rescue the hostages from Hassan.