In the five years since Malaysia Airlines Flight 370 disappeared en route from Kuala Lumpur to Beijing, other planes have been lost and found, but MH370 and every single one of the 239 people on board remain missing. This documentary sorts through the theories and charts the search. Can hi-tech hydrophones and cutting-edge submersibles provide an answer? Or is MH370 doomed to be one more of the ocean’s many unsolved mysteries?