The Girl in the Sea

In order to continue her research on whales, Dianne Bates is assigned to ORCA. She arrives there to do the research with Dr Winston Seth. Her two sons, Jason and Brett, have to go, too. Although younger brother Brett finds the underwater research station exciting, Jason is not happy about the change in scenery. Jason is given the job of tagging a whale, but fails to do so when he sees a girl in the ocean. His mother doesn't believe his story and feels he sabotages it on purpose.

Set Adrift

Vanessa Lane comes to ORCA and ends up in the same class as Jason. Brett, Zoe and Froggy play a trick on Vanessa and she gets back at Brett and leaves him in a broken boat out at sea. A storm comes up, so they can't search for him. He strands on Neri's island and meets Neri, and tells Jason about her when he comes back.

Secrets

After receiving his boat license, Jason is assigned the task of marking a driftnet, which gives him and Brett the opportunity to search for Neri. Zoe and Froggy try to obtain candy bars.

The Earthquake

Vanessa and Jason go out on a mission with the boat but Neri warns Jason that an earthquake is coming, so they return. Commander Lucas gets angry but the earthquake is for real and Damien and Lee get stuck in a room leaking water. Froggy pulls a trick with the computer called HELEN which stands for Hydro Electronic Liaison Entity 3000 to try to get them out.

Human Tears

Jason talks to Neri about the divorce of his parents. Meanwhile, Dianne is trying to convince Commander Lucas to ratify new equipment for her lab and Brett is convinced that his mother wants Commander Lucas to be his step-father.

Property Developers

Property Developers want to turn Neri's island into a big holiday resort. Jason and Neri must work together to save her home.

Toxic Waste

Neri tells Jason about a toxic spill in the ocean that is making Charley sick.When Jason is reprimanded for leaving during an important project, it is up to Lee, Brett, Froggy and Zoe to prove to Commander Lucas that the spill exists.

Day Pass

Neri decides that she wants to visit ORCA. Jason and Brett hope that she won't be there long to arouse suspicion. However, Neri's visit does not go exactly to plan.

Romance

As the kids are preparing for their shore leave to Port Douglas, Neri makes a surprise visit that forces Jason and Brett to take her with them. Damien invites Neri to see a movie but the experience frightens her and she runs off. On her own, Neri meets a young boy and helps him retrieve a stolen bracelet. Returning to ORCA, Jason and Lee find themselves alone but Commander Lucas' arrival makes for an awkward moment. Neri asks Brett what kissing is like and when he suggests she try it, she does-with Damien. Dianne and Winston come to the conclusion that Charlie is actually communicating with the small animal that accompanies him (Neri) but Dianne is not happy by Jason's lack of interest in the success of her research

Major Breakthrough

New monitoring equipment allows Dianne and Winston to hear Neri's communications with Charlie but when the tag on Charlie stops working Dianne must go out and replace it. Using the songs of Charlie and Neri, Dianne and Winston are able to attract Charlie to their location. Dianne runs out of oxygen while diving but is rescued by Neri who is forced to reveal herself to Dianne and Winston in the process. When Dianne's research is faced with being shut down, Neri replaces the lost transmitter on Charlie enabling her research to continue.

Industrial Spy

Dianne asks Neri to help with her research on whales, Dianne is especially curious as to how Neri is able to communicate with Charlie. Arrangements are made for Neri to stay on ORCA but as Dianne's work with Neri continues, Jason accuses his mother of "monstering" Neri when all Neri wants is to be a part of their family. Brett, Froggy, and Zoe chase after the spy who has been stealing Dianne's whale recordings

Neri's Secret

The spy takes the stolen whale recordings back to Dr. Hellegren at UBRI—Hellegren wants to be the first person to communicate with whales. Dianne's tests on Neri reveal a remarkable telepathic ability. Dr. Hellegren uses the stolen recordings to lure Charlie into an isolated bay bounded by an electrified net. Dianne readies Neri for her first dance but upon hearing Charlie's calls for help, Neri rushes out midway through. Curious as to why someone would steal recordings of whales, Commander Lucas decides to look into Dianne's research and discovers all about Neri.

Tough Decision

Jason and Brett round up their friends to help rescue Charlie, but Jason must also tell them the truth about Neri. Dianne destroys all of her research on Neri after Commander Lucas tells her that he will have to file a report on Neri. The kids infiltrate the UBRI command post and are able to release the net and free Charlie. A blood test done on Neri indicates that she is not human. Lee convinces Commander Lucas not to file his report. Leaving with Charlie on his annual migration, Neri tells her friends to watch for her return.