About one of the greatest mysteries in the history of exploration. It's the extraordinary story of the British explorer John Franklin who sailed into the Arctic in the mid 19th century in search of a Northwest Passage and never came back. Two ships and 129 men vanished without a trace. Their disappearance spawned the greatest manhunt ever mounted and the full story remains a mystery that has confounded explorers, historians and Franklin-searchers for 150 years.
—BBC Four