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
Journey Through the Impossible "The Children of Captain Grant" and "Michael Strogoff", as similarly spectacular plays. Verne began playing with the idea of bringing a mixed selection of "Voyages Extraordinaires" characters together on a new adventure in early 1875, when he considered writing a novel in which Samuel Fergusson from "Five Weeks in a Balloon", Pierre Aronnax from "Twenty Thousand Leagues Under the Sea", Phileas Fogg from "Around the World in Eighty Days", Dr. Clawbonny from "The Adventures of Captain Hatteras", and other characters would go around the world together in a heavier-than-air flying machine. Another novel featuring a similar trip around the world