The U.S.S. Ulysses, a 688 attack-class submarine patrolling the Atlantic, encounters five survivors of a shipwreck clinging onto a lifeboat hundreds of miles from land. Breaching Navy orders the submarine's commander decides to rescue the survivors. Once on board they reveal their true intentions... they are ruthless terrorists and within hours have taken control of one of the world's most advanced vessels and all her nuclear arsenal. As the world is held hostage, one man embarks on his 'mission impossible' to save his life, his country and the world from the jaws of nuclear holocaust.