While on leave from the Air Force in Austria, a young American serviceman named Will attends the sumptuous Opernball (opera ball) in Vienna. There he meets Natasha, a beautiful Hungarian refugee. It's love at first sight for the couple, despite the disapproval of her family, and they embark upon a secret courtship. Yet when their relationship is exposed during a fateful trip to Paris, they are forced apart. Nineteen years later, Will returns to Vienna; to his surprise, Natasha is there as well. Their tender reunion is cut short, however, when Natasha reveals that she is being blackmailed into working for the KGB. Will, who in his youth dreamed of rescuing a beautiful damsel in distress, suddenly finds himself attempting to do just that-with no guarantee of a happy ending.