Mimmi's insatiable curiosity leads her to land school, where Erik quizzes her about the symbols he saw in the merman chamber, hoping she knows their meaning.
A charismatic newcomer, Dr Denman, tempts Lewis with the promise of scientific fame and fortune. Will he abandon his friends and risk their secret, all in the name of science?
The effects of the full moon turns Emma into a carefree, wild mermaid. At her father's birthday party she's the opposite to her usual, organised self. Can the other girls stop her before all is revealed?
Rikki gains an admirer in Emma's younger brother Elliot when she saves him from drowning. She lets him down hard causing him to run away and hide in the fernery. The girls find him just as the watering system is about to start.
Kim reads Cleo's diary and finds evidence of mermaidness. She spies on the girls and decides Miriam is the head mermaid. Miriam and Cleo enter the Queen of the Sea contest where Kim tries to prove her theory but only succeeds in upsetting Miriam.
The first years are given trust exercises to help forge connections with their pas de deux partners. Tara is frustrated when Christian refuses to participate, however they connect unexpectedly when Tara follows him to the beach.
When Tara's crush on Ethan threatens to derail her friendship with Kat, Sammy gets her to write a pros and cons list to clear her head. As the roommate war escalates, Abigail wins a decisive victory - emailing Tara's list to the whole school.
Tom is out of control so Rhydian, Shannon and Jana turn to Segolia for help.
Jana, Tom and Shannon go to Segolia where Tom discovers something mysterious and terrifying that changes his life.
After Kuru's visit, Alexandra's family is unusually accommodating. Kuru reports in Manjipoor that the princess isn't ready for the throne, but the guru is confident she'll grow into it and gives him the magical royal runes. Finding out she's adopted as Kuru said, she goes crazy, wants to run away and tears up a family picture.
Alexandra dreams of a singing career, in a pop band with friends Marcus, JB Deekes and Amanda Tucci. At her birthday party they get a complete surprise visit. The mysterious Indian Kuru, riding the often invisible elephant Anala, tells them she's in fact the magical princess-heir of Manjipour.
When ZOEY and KIKI, two irrepressible girls from another galaxy land in Lightning Point, their dreams of surfing the waves of Earth's oceans have finally come true!
Lars af Dracas overhears the Noaidi predict the future of all vampires if the clans don't reunite, they will go extinct. His father sends out a message to the other four remaining clans to join forces. On the mystical ship the Elisabetha, the other vampire clans come to an understanding. At the market Alisa's fangs accidentally pop out and humans panic because she's a vampire.
Zac goes on a camping trip to Mako with his father, on the night of the full moon. Cam and Erik are invited too. Zac has another vision of the merman chamber, shared by Mimmi.
Cam is on lifeguard duty when Erik quizzes him about Zac's connection to Mako. Erik is splashed and rushes into the ocean, disappearing.
Zac and Erik enjoy their first swim together but are shocked to find Evie's Dad's boat at Mako, where he has begun taking dive tours.
Determined to live her life as normal, Cleo confronts her fears and lands a job at the Marine Park, helping out to feed the dolphins. Despite her precautions, she gets splashed and, just as she's about to turn into a mermaid, a mysterious Old Woman, Miss Chatham, comes to her rescue.
When Emma and Rikki save a sea turtle from a fishing trawler's net, they are mistaken for sharks. A shark hunt ensues. Cleo, getting over her fear of water, saves another turtle, but she is trapped.
Annoying Miss Popularity, Miriam, is having a pool party that the girls don't want to miss. But it's a risky activity for three mermaids: their secret could be out. Spurned by Lewis, Rikki discovers her mermaid power is to boil water at will!
Cleo and Emma meet new girl, Rikki, and find themselves stuck on Mako Island where they are transformed into mermaids. As well as growing tails, the girls find they have powers over water.