While looking through an old sea-chest found in his attic, Captain Haddock chances upon the diaries of his ancestor, Sir Francis Haddock. This legendary sea dog achieved fame through his renowned run-in with the fearsome pirate Red Rackham. So are the words of Sir Francis Haddock just another chronicle of life at sea? Certainly not! His journals speak of a fabulous hoard of jewels: for Tintin, Captain Haddock - and a gang of crooks - the treasure hunt is well and truly on. But as the search continues, the plot thickens...