In 1845, maverick Royal Navy captain Sir John Franklin sailed off the map of the known world with 128 men, to chart the elusive Northwest Passage. No trace of them was ever seen again. Until now. In September 2014 a multi-million-dollar state-of-the-art expedition made the astonishing discovery of the Victorian ship HMS Erebus, intact and upright on the Arctic sea floor. It’s the culmination of a 150-year-old mystery and is being hailed as the find of the century. This Secret History documentary has exclusive access behind the scenes of this momentous expedition. The story unfolds in the freezing Arctic, on the search vessels on the 2014 expedition, from their battle with heavy sea-ice that threatened to stop the search entirely, to the dramatic chain of events that led to their historic discovery.