in which Kal's mother explains that Neri's father was to repair the damage done to Earth's oceans with an advanced device called the Synchronium. She then dedicates her life to her father's cause, giving her a genuine sense of purpose that she had perhaps lacked earlier in the series. Kal grows jealous of the strong bond between Neri and Jason Bates, and begins hating Neri's friends on ORCA. As protest, Kal leaves the island. Neri and her ORCA mates go looking for him, but are unable to find him as he's been captured by UBRI. UBRI tricks Kal into believing that the male should lead (as he had been indoctrinated into the matriarchal social mores of his people), and he creates an alliance with Dr. Hellegren to steal the Synchronium pieces that Neri and Mera have hidden in a secret cave. While the primary cast gets new motivations by UBRI's move to ORCA and Kal's appearance on the island, the secondary cast radically changes at the outset of the third season. All of the original kids are replaced by a new crew, and more adults are added to the ORCA staff. As Neri begins her father's mission, she is drawn farther and farther away from her island. Beginning in the middle of the third season, some episodes are primarily based on land. By the fourth season, some episodes are set in Egypt, and her father's quest eventually leads her back to the "Ocean Planet", her home planet. Most of the plots involving the secondary kids on ORCA are reduced in the final season, in order to allow for greater exploration of Neri's home world. Several new characters of Neri's species are introduced. Likewise, the threat of UBRI fades, to be replaced by a new organization, PRAXIS (Preventative Response and eXtraterritorial Intelligence Service) and by rebels on the Ocean Planet. This group is dedicated to protecting against any threats posed by extraterrestrial life, and its agents come to believe Neri and her people are a problem for Earth. They thus chased Neri and the Bates boys around the world. When a mysterious underwater pyramid is discovered in the ocean, Neri and the Bates boys enter it and discover more about the Ocean Planet, and Neri's mission on Earth. When the rebellion in the Ocean World is growing, Mera escapes to Earth and is reunited with Neri. But PRAXIS sees this pyramid