To rejoin the pod, Sirena, Lyla and Nixie must turn Zac from part-time merman to full-time land boy. With the power of Sirena's Moon Ring, the mermaids give themselves legs.
Young mermaids of the Mako Island pod, Sirena, Lyla and Nixie have the task of keeping trespassers off the magical island.
Lewis has a bad dream about Cleo being discovered as a mermaid. Elliot asks Lewis for advice on girls and Lewis obliges, just to keep him happy. Elliot asks Kim out on a date to the marine park but Kim goes along with it just to take advantage of Elliot paying for everything. When Don forces Cleo to go as chaperone and Elliot begs Lewis to come, Lewis and Cleo find themselves on the date too.
Nate is still trying his best to get Cleo to like him but to no avail. Lewis and Zane find an old myth about mermaids is true - the scent of ambergris sends them wild. Ambergris was once used in perfumes and is deposited by whales, it's extremely rare but Zane acquires some. Zane's plan to use it backfires when sleazy Nate gets hold of the scent and quickly has all three mermaid girls on his arm!
Emma is annoyed to find the one guy she can't stand suddenly appearing around the juice bar - Ash. When she thinks she's going to get a promotion at work, Emma is even more annoyed to find that Ash has been given the job ahead of her. As Emma and Ash clash over how the juice bar is run, we discover it's over a lot more they're secretly attracted to each other.
Don forces the family to go camping on Mako Island during a Full Moon. Cleo can't get out of it so invites Emma and Rikki for back-up. Lewis inveigles himself to go too but when he tells Charlotte, she pressures him into taking her as well! The girls are furious with Lewis but he's in a bind.
Realising that Saskia's continuing critique of her dancing could jeopardise her mid-year exams, Tara takes action, while Christian ditches his pas de deux exam to hang out with Kat. Wired on energy drinks, an overtired Sammy kids himself that he's blitzing exams, and puts Abigail in danger as a result.
Tara's concern about the time she spends with Christian impacting her dance study leads to her to suggest they ‘pause' their relationship, and Ben tries to impress Kat through an ambitious choreography assignment. Meanwhile Grace has cause to be jealous when Abigail and Ethan continue to work closely together.
Rhydian unexpectedly returns on the night of the full moon, chased by wild wolfbloods as Tom discovers Shannon spying on the Smiths with a surveillance camera hidden in the Den. Maddy's overjoyed to have Rhydian back and persuades her parents to help him re-adjust back to life in Stoneybridge.
Shannon is worried about the wolves and their safety now people know they exist, they may be hunted. She plans to inform the Department of the Environment so they can protect the wolves, but first needs proof that the wolves exist and she knows how to get it - Carl's wolfbait! Maddy and Rhydian are worried, they have to get the bait before Shannon gets her hands on it.
It is the day of the full moon and Maddy and Rhydian aren't looking forward to a night in the den. Rhydian tries to talk Maddy into escaping, but Maddy knows she can't - her parents would be furious! Shannon has been trying to forget about the beast by throwing herself into other interests.
Rhydian is dabbling with his Eolas powers in school, showing off to his school mates. Maddy can't understand how he is doing it, the tricks go beyond Wolfblood senses and speed. Rhydian shares his secret with Maddy. It's something his mum taught him, Eolas, which wild wolfbloods use to connect themselves with nature.
Marcus got the band a gig in his uncle Harry's café, where Zom Records executives have lunch, but the stage is too small, so they must perform a duet by Marcus and Alex, who abuses some minor magic. Omar informs the elders one of Anala's magical headdress jewel was stolen.
When OLIVIA rings AMBER about a surprise waiting at home for her, AMBER would never have guessed that the surprise was her Dad KEITH!
As new clan leader Lars has to vote with the Elders on Alisa's and Calvina fate. Lars' uncle General Ragnar is furious that Lars won't do things the old Dracas-way and secretly makes contact with a familiar evil. Inger offers to help Alisa and Ivy find the prison of eternal light. On their journey, unaware to them, they are being followed by a hooded stranger.
On the night of the full moon, the pod plans to attack the dragon by conjuring a massive lightning storm. Weilan realises the dragon is Nerissa trapped by a spell.
While at the ‘Secrets of the Deep' book launch, the mermaids realise that a bracelet on display is the key to destroying the dragon, according to the Legend of Jiao Long.
A spell goes wrong and turns Rita into an old woman. The mermaids rush to find a cure so Rita can attend a school board meeting to decide whether she or Ms Trumble is Principal.
Emma starts acting very weird after pricking her finger on a mysterious barb of coral, suddenly becoming ravenous for things like anchovy flavoured fish food! Cleo's fish, Hector, exhibits the same behaviour. As Hector begins to look very sick, Emma turns into a mermaid at the marine park, swimming about in front of the glass in the viewing area.
Zane hears of treasure under the ocean and enlists Rikki to help find it, after all a mermaid can search the bottom of the ocean pretty fast. Rikki is reluctant until she discovers her dad is having trouble paying the bills - and they might be forced to move. Rikki gets Emma and Cleo to help, but conceals her true reasons for wanting the treasure.