When the whaleship Essex set sail from Nantucket in 819, the unthinkable happened. A mere speck in the vast Pacific ocean - and powerless against the forces of nature - Essex was rammed and sunk by an enraged sperm whale, and her twenty crewmen were forced to take to the open sea in three small boats. Ninety days later only a handful of survivors were rescued - and a terrifying story of desperation, cannibalism and courage as revealed...