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 are quickly captured and brought inside the vessel, where they meet its enigmatic creator and commander, Captain Nemo. The rest of the story follows the adventures of the protagonists aboard the creature—the submarine, the "Nautilus—"which was built in secrecy and now roams the seas free from any land-based government. Captain Nemo's motivation is implied to be both a scientific thirst for knowledge and a desire for revenge upon (and self-imposed exile from) civilization. Nemo explains that his submarine is electrically powered and can perform advanced marine biology research; he also tells his new passengers that although he appreciates conversing with