Jean, a young French boy who builds airplanes, teams with his uncle to enter a flying competition at the 1899 World's Fair in Paris. The young inventor crosses paths with an enigmatic girl and her pet lion. It's there that the preteen Jean meets and immediately falls for the exotic Nadia, who leads an unhappy life as a circus performer. Jean turns protector when Nadia is chased by a trio of bumbling villains who are after the mysterious 'blue water' in Nadia's necklace. Their pursuit leads to the open sea, where Jean and Nadia board an American battleship searching for a vengeful sea monster, ultimately revealed as Captain Nemo's submarine, Nautilus. Join Nadia and Jean as they travel the high seas in search of Nadia's homeland and her past, their only clue the mysterious jewel Nadia wears. Can they unravel the Secret of the Blue Water before it is too late?