Jean, Nadia, and King are rescued by an American battleship in pursuit of sea monsters, who have apparently been responsible for sinking ships. That night, the battleship is attacked, and Jean, Nadia, and King are thrown overboard....

Marie and King run off to explore the island, when they find themselves both lost and pursued by Gargoyle's soldiers. Sanson comes to their rescue.

Jean's latest invention goes disastrously wrong and accidentally alerts the Garfish to attention. Nadia's detestation of Nemo and jealousy of Jean's friendship with Electra dangerously intensifies--until she finally learns that the Nautilus is merely fighting to destroy Gargoyle and that Electra poses no threat to Nadia's relationship with Jean. During all this, Gargoyle is informed of the Nautilus's prescence and devises to set yet another deadly trap....

Jean, Nadia, Marie, and King are reunited with Grandis, Sanson, and Hanson. Together they all decide to live as a family on the new island, which Jean theorizes is moving.

A violent row between Sanson and Hanson turns into a race between two mechanical lions resembling King(!).

When King gets captured by Grandis' ex-fiancee, our pals set off to save him.

Gargoyle's battleships appear over Tartessos. To save Jean and the others, Nadia surrenders herself... but not before Jean swears to save her. Forced to flee from Gargoyle's battleships, our pals run into Captain Nemo and his crew, who have survived... and now operate a superpowerful battleship called the New Nautilus.