A Boeing 727 airliner belonging to Transcon Airways is scheduled to depart from Los Angeles en route to New York via a pit stop in Salt Lake City. Flight 602 is under the care of Captain Pete Douglas, First Officer Stan Burkhart and Second Officer Mike Fuller. The overall atmosphere on the flight is upbeat, despite Captain Pete Douglas' absent-mindedness due to his worries about his wife's upcoming surgery. Her doctors want to remove a lump in her breast before it becomes malign. The captain also worries about the announced snow storm that prompted some airports to close. He hopes to arrive to his destination in New York before the storm intensifies. The airplane makes its scheduled stop in Salt Lake City where it's refueled and takes on a few more passengers. Among the new passengers are an extradited prison inmate and his U.S. Marshals escort who are also traveling to New York. The aging Marshal has heart problems but is otherwise strong as a bull and is well armed. After leaving Salt Lake City, the Federal Marshal has frequent heart pains but he tries to put on a brave face in front of his handcuffed prisoner. He makes it clear to the extradited killer that he's well armed and that he won't tolerate any violence from the part of his prisoner. However, the handcuffed inmate is patiently bidding his time, waiting for a slip-up from the part of the Marshal. If the armed Marshal could be over-powered, the inmate could grab the magnum revolver and he could take control of the aircraft. The lives of all on-board would then be in grave danger.