When it does not turn up, they try searching for it in Rita's fish order, but it is not found. Evie ultimately catches a glimpse of the moon and falls under a moon spell, making her hyper and longing to be with Zac. Erik tries to bribe Cam into giving him the stone but Cam refuses to lose his friendship with Zac twice and, instead, gives it back to the mermaids. As leader of their small clique tries to make the transformation from Zac reversed immediately. Much to Cam's humiliation, any attempt he makes to impress Carly, she does better. Ondina is given the task of teaching a class of younger mermaids in mermaid school.
When Layla and Nixie get into the hair, Sirena always acts as peaceful arbiters. He races to Mako Island to get the trident, with the girls in hot pursuit. Although impressed by his heroism, the mermaids still believe they must take his powers away or he will eventually make a mistake and expose both himself and mermaids. To get access to Rita's house, he convinces Evie and David to interview Rita at her home for the school magazine. Zac hides Evie in the café's refrigeration room and then runs off to stop the spellcasting while Cam and Sirena keep Carly and the new waiter, Erik, from entering the room and seeing Evie with a tail. The next day, Zac finally accepts Mimmi as his sister.
Afterwards, Sirena decides to stay with Lyla and Nixie rather than return to the pod. When Weilan takes the box to school, their science teacher gets too close to it and is also sucked in. The next day, Veridia lifts the girl's banishment and informs them that the pod will return by the next full moon. A mysterious bracelet at the exhibition is noted to be associated with the. Rita reveals that the shell is a wishing shell and only the person who found it can use it.
Fed up with always having to cover for Zac, Cam pushes Zac into the pool and abandons him. The lotion eventually wears off and Rita comes back to her senses, revealing that she helped a recently rescued and struggling dolphin. She also gives him Sirena's carved shell and asks him to throw it into the ocean in hopes it will get to Sirena's sister, Aquata. Feeling guilty, Ondina asks Zac and Evie for their help to search for her. While out for a swim, the two narrowly avoids being run over by Doug's boat. On the night of a full moon, they are put on patrol and tasked with keeping humans away from Mako Island.
They return to the cafe where Sirena ends up singing with David after the two admit their feelings for each other and share a kiss. The enchantment does not seem to work at first but later that night, the box activates and sucks in Poseidon. A newly enrolled Erik is obsessed with finding out more about the merman chamber on Mako Island. As they try to arrange a formal party, no one shows up much to Cam's disappointment. It features 16 half-hour episodes. With the use of Sirena's Moon Ring, they are able to gain legs of their own.
Sirena comes back to her senses and Ondina uses her moon ring to send David back to his boat with no memory of what happened to him that night. Realising that Zac has taken the trident to school, the girls show up at school to search for it. They discover a mysterious chamber on the island from Zac's vision. Zac agrees under the condition that he goes alone. The girls convince Zac to give this a try.
She has him close his eyes while she gets in the water and successfully helps him to connect with a dolphin. The four come together with their powers and destroy the trident, preventing Cam from executing his plan. June 2016 With the full moon approaching, Ondina tries to warn Erik not to activate the merman chamber, but Erik refuses to listen even to her. He introduces Mimmi to Karl, whom he met in America. Later, he sneaks into the grotto through the underwater entrance with the trident in hand to check it out properly. With her cover blown, Rita tells the girls she must leave town before Zac exposes her.
Erik overhears the two talking about Mako and heads to the island to explore it. The two find a symbol of a trident on the outcrop but when Erik touches it, he is teleported into a realm of endless water with no way out. . The others are worried given the history of mermaids and mermen, but Ondina expresses trust and possible interest in Erik. But he has another problem — his part-time job as a lifesaver on the local beach. He isolates himself from everyone else and refuses to accept Mimmi as his sister. He succeeds and the two mermaids reluctantly agree to collaborate with Evie in the future.
He successfully deactivates the chamber and saves the mermaids but seemingly dies in the process. June 2016 The next full moon is approaching and Zac will have an opportunity to learn about what the merman chamber does. Unfortunately, Evie decides to join the pod in the fight and she enlists Carly to perform the same task as Cam. Meanwhile, Joe informs the marine park of the dragon he saw last night. Meanwhile, when Evie worries about an upcoming exam, Zac uses his powers to sneak into Rita's office and find the questions on the exam.
Evie, Zac, and the three mermaids must stop the animated mop before Evie's father comes home. When Carly later shows up, demanding answers, she finally discovers Zac's and the girls' secret. Confused, the girls leave and meet a younger Rita who does not recognise them. Confused, the girls leave and meet a younger Rita who does not recognize them. Back at the beach, Erik is accidentally splashed and is forced to rush into the ocean. Meanwhile, Cam lies to Nixie, telling her that Zac wants the trident back and offers to help her move it to a secure location.