The Seventh Cycle
February 13, 2015 (Netflix)
February 15, 2015 (TENplay)
Lyla and Nixie have left Sirena to join in a search for a new home. Out at sea, Sirena is unable to convince the mermaid council that Zac is not a threat to them. Two new mermaids, Ondina and Mimmi, head to the mainland with Sirena to try to remove Zac's powers. The two try to warn Zac about his impending encounter with his seventh full moon since becoming a merman, but Zac insists he doesn't need their help. Undeterred, that night, Ondina and Mimmi lure Zac to the Moon Pool and attempt to use a powerful spell to remove his powers. Evie, fearing the mermaids may harm Zac, comes to his rescue, only to be transformed into a mermaid herself.
A few months have passed since the trident was destroyed in the confrontation with Cam at the Moon Pool. Zac is now content with his life as a merman while Evie is content with being a part of Zac's double life. Due to their confrontation over the trident a few months ago, Cam and Zac are no longer friends and refuses to speak to each other.
Nixie and Lyla had recently left the Gold Coast to join a party searching for a new home for the pod while Sirena stays behind to continue her effort in reclaiming Mako Island for the pod. Out at sea, Sirena meets with the mermaid council but is unable to convince them that Zac is not a threat to the pod. A pair of mermaids, Ondina and Mimmi, overhear Sirena's conversation with the council and decides to head to the Gold Coast with Sirena to try to remove Zac's powers. The three mermaids swim to Rita's grotto where Ondina and Mimmi get legs for the first time.
At the café, Ondina and Mimmi introduce themselves to Zac. The two warn Zac that tonight would be his seventh encounter with the full moon since becoming a merman and tell him that he would need their help to resist the pull of the moon. Zac, however, stubbornly refuses their help and insists that he can resist the full moon on his own. Ondina becomes aggressive and demands that Zac follows her orders going so far as to attack him with her powers. Refusing to let Ondina bully him, Zac retaliates with his powers. The resulting scuffle ends up shaking the cafe and getting them splashed by coconut juice, forcing them to jump into the water before they transform. In the ocean, Ondina gives Zac a menacing glare before taking her leave.
Later, Zac and Evie ask Rita about the seventh moon cycle. She tells them that the seventh cycle could enhance Zac's powers and make his connection to Mako Island stronger. Zac agrees to stay with Evie that night so Evie can keep an eye on him.
Ondina and Mimmi meet up at the Moon Pool and devise a plan to remove Zac's powers. That night, Zac and Evie attend a performance by Sirena and David at the café. Ondina arrives to keep an eye on Zac. Meanwhile, Mimmi sneaks into Rita's grotto and uses the ingredients there to make a potion that she believes will help remove Zac's powers. She then meets up with Ondina at the café. The full moon rises and causes Zac to have a vision of Mako Island and the Moon Pool. Mimmi, for some unknown reason, also has the same vision but she brushes it off. Zac tries hard to resist the moon's pull but the moon spell overpowers him and he feels drawn to Mako Island. Cam tries to prevent him from leaving but Ondina and Mimmi use their powers to toss him aside. Seizing his opportunity, Zac jumps into the water and swims off to Mako with Ondina and Mimmi following him. Sirena realizes that Ondina and Mimmi wanted Zac to swim to Mako as part of their plan. Evie, fearing the two mermaids may harm Zac, follows after them in a boat with Cam. Sirena tries to go too but is prevented from leaving by David.
Zac surfaces in the Moon Pool just as the full moon begins passing overhead. Ondina and Mimmi arrive and begin using the potion on Zac in the hopes of removing his powers. Outside, Evie and Cam arrive at the island. Wasting no time, Evie dives into the water and finds the underwater entrance to the Moon Pool. She surfaces in the pool next to Zac with Ondina and Mimmi still casting their spell. Evie's presence interferes with the spellcasting and she is knocked unconscious. The two mermaids, realizing the potion didn't work, retreat from the pool while Zac wakes Evie up.
The next morning, Ondina and Mimmi inform Sirena of the events from last night. When the two mentions Evie, the girls realize, to their horror, that Evie was in the Moon Pool when the full moon was still passing overhead.
Back on land, Zac checks on Evie at the marina, who assures him that she's alright. With the three mermaids in the water nearby watching, Evie sprays herself with water and gets the shock of her life when she falls into the marina and is transformed into a mermaid!
- Zac: This is my island. Leave
- Mimmi: Your island?
- Zac: You heard me.
- Ondina: We'll see about that.
- Ondina: Are We?!
- Zac: Yeah
- Sirena - Amy Ruffle
- Ondina - Isabel Durant
- Mimmi - Allie Bertram
- Zac Blakely - Chai Hansen
- Evie McLaren - Gemma Forsyth
- Erik - Alex Cubis
- Cam Mitchell - Dominic Deutscher
- David - Rowan Hills
- Senior Mermaid #1 - Reiko Austen
- Senior Mermaid #2 - Natalie Prigoone
- Younger Mermaid #1 - Anita Munro
- Younger Mermaid #2 - Yasmin Honeychurch
- Poseidon - Monte
- Rita Santos - Kerith Atkinson
- The events in this episode takes place roughly three months after the events of Decision Time.
- A new beat can be heard in the opening theme song.
- Ondina and Mimmi debut in this episode.
- Gemma Forsyth is promoted to series regular.
- Lyla and Nixie are only mentioned once.
- Evie transforms into a mermaid in this episode.
- Zac seems to be excited when Evie transformed into a mermaid.
- Although, Natalie O'Donnell appears as Veridia in this episode, she is not credited.
- Brooke Nichole Lee as Carly Morgan is credited, but does not appear in this episode.