Teens Jack, Marco, Aly, and Cass begin a quest to find seven pieces of Atlantis's power that were hidden long ago and that will, if returned to Atlantis, save them from certain death due to the genetic abnormality that also gives them superior abilities.

Jack and his friends desperately search for the rest of the lost Loculi and confront the armies of Artemis in order to rescue Aly, who has been pulled back into Atlantis by King Uhla'ar.

Shelly Siren loves playing on Trident Academy's Shell Wars team. But is she ready to complete in the Shell Wars Championships in the fintastically famous city of Atlantis? As part of their trip, the mergirls get a tour of Atlantis and swim through Poseidon's Temple where Shelly sees a spookfish, which according to legend, carries a horrible curse.

When Paulina, one of the Thea Sisters, finds a strange blue-skinned boy unconscious on the beach, the sisters set out to solve the mystery of who the boy is and where he comes from--and how to return him to his home.

Spending the summer after sixth grade at his great-uncle's oceanside museum, Thatcher and local girl Trudy team up to help Shoal, one of the people of Atlantis cursed by a witch whose head still survives, and who has an army of monstrous creatures helping her.