Episode 1
The new commander at ORCA, Commander Bryne arrives with her son Mick, who is a paine for all the others. Jason and Brett go to Neri's island and find a silver piece of jewlery in the shape of the island. Dr. Hellegren from UBRI is searching for Charlie, but the helicopter crashes and he ends up in a life boat at sea. Neri tries to help him, but he captures her. With Charlie's help she gets away. Sam Phillips (a sailor) arrives at ORCA.
Episode 2
Neri is back at ORCA and Dianne shows her the research she's made. Brett gives her the silver piece they found. Dianne has to make a map over the ocean for Commander Bryne and Sam will be driving the boat for her. Neri, jason, and Vanessa go looking for what's on the map (the silver piece is a map) and find some wierd printing on a rock that even HELEN can't read. Eventually they find a hidden spacecraft on the ocean bottom.
Episode 3
Neri finds the entrance to the spacecraft and she and Jason swim in. They finda signal transmitter that Froggy fixes and slowly the spacecraft is coming to life again. They also find a hexagon which is a 3D movie with a recording of Neri's father. He tells her why they're here and that she's got a sister, Mera.
Episode 4
Mick tries to make Froggy change his grades. Sam is looking for minerals in the ocean survey they'er making. Roxy's sister Joanne goes out with Winston in the boat, but falls into the sea and gets rescued by Neri. She thinks Winston did it. When Neri's near the boat the survey gets much better. Froggy and HELEN find an old newspaper cut about Mera.
Episode 5
They find Mera (who's called Jane Seaforth) at an institute for weird kids. Dr. Hellegren also finds Mera and decides that she's going to UBRI. Neri helps Dianne and Winston with the survey. Jason, Froggy and Vanessa talk to Mera and she promises to follow them if they prove that she can trust them.
Episode 6
Froggy gets a fake ID for Mera. Mick invites Vanessa to the dance as a joke. Dr. Hellegren tells Mera that she's going to UBRI. Jason, Brett, Froggy and Zoe pick up Mera and when she sees Neri's silver piece (she has an exact copy herself) she goes with them. Finally Neri meets Mera and Neri shows Mera her island.
Episode 7
Mera doesn't like living on the island and she's begining to wonder why she ever left. She gets scared by Charlie. Mick finds out that Vanessa is afraid of spiders and gives her a spider as a birthday present and that causes a fire. Froggy finds out that Mick never learned to read. Dianne is having a date with Sam which Jason and Brett don't like.
Episode 8
Dr. Helegren sends Forsyth and Liselle as spies to ORCA. Mera falls down a cliff on the island and Neri hears her call for help and rescues her. Slowly Mera begins to like living on the island. Mick gets assigned to the boat by commander Bryne and they have trouble keeping him away from seeing Neri. Dianne asks Sam to help with the survey results and he finds titanium.
Episode 9
Dr. Hellegren searches through the islands but finds nothing. Mick eventually sees Neri and Mera on the screen but everyone says he's seeing things. Liselle gets interested in what he says. Dianne asks Sam to keep quiet about the titanium but Sam won't promise anything.
Episode 10
Forsyth hides a transmitter on Dr. Bates boat so that UBRI can follow them. Commander Bryne assignes Froggy, Zoe, Joanne, Roxy and Mick to the boat. Divers from UBRI try to catch Neri and Mera but Charlie saves them. This leads to that everyone on the boat finds out about them. Everyone except Mick promises to keep the secret.
Episode 11
Winston catches the transmitter from the spacecraft on his epuipment and goes to Neri's island to search for something. He meets two strange people. Mick falls into the water and gets rescued by Neri, and then he pronises to keep the secret also. Neri helps him learn to read. Vanessa finds out who Liselle is. Dr. Hellegren finds out that Neri and Mera are on ORCA. Forsyth puts so much pressure on HELEN, that she collapses and dies, but Froggy won't believe it.
Episode 12
Neri escapes from ORCA to try to save Mera and Charlie, but Brett and Sam follow her to tell her she is wrong. Sam promises to keep quiet about the titanium, to try to win Diannes heart and to get along with Jason and Brett. Froggy finds Forsyth's hidden transmitter to UBRI. Vanessa and Mick become friends. The two strangers want to take Neri and Mera home to their planet.
Episode 13
Mera wants to go and Neri fells that she has to. Froggy succeeds in getting HELEN alive again (a surprise for Commander Bryne). HELEN tells them about Forsyth and Commander Bryne arrests Forsyth and Liselle for spying. Neri, Mera, Jason, Brett, Dianne and Sam go to the island to say goodbye. Mera leaves with the strangers but Neri stays. Dr. Hellegren sees the spacecraft leaving and gives up.