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....

Four months afterward, the Gratan is nearly repaired, and soon our pals will set off for Africa. But first Jean and Nadia go off on a hike which leads them to a mysterious underground cavern that turns out to be more than they suspected. The exploration culminates when Nadia falls into a trance and vanishes behind a wall, leaving her clothes in Jean's arms! During all this, Ayerton tries to make his move on Grandis.

Finally, our pals arrive at Nadia's real homeland--Tartessos. As they tour through its long forgotten ruins, our heroine finally reveals her darkest secrets... including who she is. How will all this affect her relationships with everyone, especially Jean?

The New Nautilus and Gargoyle, now aboard Red Noah, face off in a spectacular duel of pyrotechnics, lasers, and, ultimately, wills. Midway through, both crafts head into outer space. After finally breaking in, Nemo, Jean, and Electra confront Gargoyle, who now has Nadia under his control.