Dark Waters (Once Upon a Time) is to take Snow's heart. The Land of Untold Stories is revealed to be the Mysterious Island from the book as the same name. The "Nautilus" is based on the submarine from "Twenty Thousand Leagues Under the Sea". Captain Nemo based on the protagonist from Jules Verne's novel "Twenty Thousand Leagues Under the Sea". Hook refers to the giant squid that attacks him as a kraken. The kraken is a legendary sea monster of giant size that is said to dwell off the coasts of Norway and Greenland. The episode posted its lowest numbers so far in the series, as
Twenty Thousand Leagues Under the Sea invitation to join the expedition, which he accepts. Canadian whaler and master harpoonist Ned Land and Aronnax's faithful servant Conseil are also brought aboard. The expedition departs Brooklyn aboard the United States Navy frigate "Abraham Lincoln" and travels south around Cape Horn into the Pacific Ocean. After a long search, the ship finds the monster and then attacks the beast, which damages the ship's rudder. The three protagonists are then hurled into the water and grasp hold of the "hide" of the creature, which they find, to their surprise, to be a submarine very far ahead of its era. They