A warship is sent to investigate a 'creature' that is sinking vessels in the middle of the sea. The warship itself is sunk and three survivors end up aboard the 'monster', a submarine called 'The Nautilus', skippered by the insane but brilliant Captain Nemo (James Mason). The rest of the adventure includes a battle with a giant squid. Disney's first live action feature sticks closely to Jules Verne's 1869 book.