Headed for South Korea, a Boeing 767 crashes into a hillside several miles from the runway. As the nation mourns its worst-ever air disaster, investigators face puzzling evidence: The surviving captain of the Air China flight claims that everything was normal, while air traffic controllers testify that the radio communications were anything but. Evidence reveals the crew had mishandled the precisely timed series of turns before touching down on the runway, and investigators are faced with the mystery of why the crew failed to correct the issue.