Imprisoned by the wicked Gargoyle, Nadia is forced to admit that she gave her Blue Water to Jean before turning herself in (to save Marie and King from a horrible fate). As the search for Jean is on, the boy desperately tries to find her. Simultaneously, Grandis, Sanson, and Hanson, who have also been imprisoned by the soldiers, break out of their prison cell and attempt to escape. While Gargoyle tours Nadia around his base, he showcases Neo-Atlantis's secret weapon, a tower known as Babel with the power to obliterate an entire island!

In pursuit of Gargoyle, the Nautilus becomes trapped in a dangerous underwater mine field. Sanson and Hanson jump aboard the Gratan to clear the mines before they detonate. Jean sneaks on to help the two men....

The victims of Gargoyle's latest attack are taken to the long-forgotten underworld of Atlantis to be buried. While there, Jean discovers that his father's ship was sunk by the Garfish. Nadia also learns that she must keep the Blue Water at all costs, no matter what pain or damage it may cause.