When Rita's Cat, Poseidon steps through a puddle of mermaid powders, he is transformed into a person. A girl - identical to Evie!
Rikki fears Ryan's explorations on Mako Island will uncover their secrets but Cleo and Bella discount her concern.
Cleo's introduced to Ryan, a young geophysicist who's working for Samantha. Rikki doesn't react well to Cleo consulting Ryan about the Mako rock and a fracture begins to appear in the trio.
Rikki's frustrated by the water attacks and goes to Mako Island on a full moon to confront the strange force in the Moon Pool.
Sophie uses Bella's idea for a fundraising concert and presents it as her own to Rikki to gain publicity for the cafe.
Grace continues to make a play for Zach's attention, leading her to manufacture a serious accusation as Christian's resolve to bounce back from his Prix de Fonteyn elimination drives him toward some reckless behaviour. The winners from the Prix ...
The Academy students experience stinging prejudice from the judges during the National Round of the Prix de Fonteyn, just as Sammy's father visits the competition to watch his son dance for the first time in years.
An unexpected arrival puts Rhydian's leadership skills to the test in a matter of life and death.
Rhydian, Shannon and Tom face a new future – and an old foe.
Just when Vashan prepares for his coronation, he discovers Diva has magical powers, but too late: she throws him in the dungeon. When Omar and while he flees Kuru find out, she tries to kill them, but Anala saves them by transportation to the Wilson home. Alex uses magic to cure Omar's wound.
Daniel has knocked the wall through, determined to investigate these amazing tunnels which lead directly into the den. Emma is convinced their time at the house is over. Their secret is out. But Maddy and Rhydian try to persuade her that Liam may not know what he's seen or where he was. They will go into school, having phoned Tom and Shannon to find out what they can.
Liam returns to school after his ep 10 trauma. Maddy and Rhydian aren't in registration. It's the day of the full moon and Tom surmises they are out having fun. But what they are actually doing is fleeing for their lives from Alric who is out for revenge. Maddy tricks Alric into using Eolas under the electric power lines and they escape. In school, oral exams are taking place in the hall.
Having learned Omar is her dad, Alex has ran back to the Wilsons. Kuru comes pack, take his leave from the Wilsons and offer generous gifts. They include a model and wood for a Manjipoorean gazebo, which dad Jim is unable to construct, but he gets JB to help and talks him into making up with Alex.
The day of the Lightning Point Junior Girls Surfing Competition is here and everyone from Lightning Point is ready to compete. Except ZOEY.
Alisa and Dracula are rushed on board of the ship. Both badly wounded and unconscious. What the hell happened to Alisa and her friends in the standoff against Dracula and his Upiry army? Lars feels he let everybody down, but Inger and Ivy try to convince him that he needs to be strong and find a way to get Alisa to wake up.
Sirena's sister Aquata returns to Mako with wonderful news – Sirena can return to the pod! Unfortunately, the invitation isn't extended to Lyla and Nixie.
The Trident is active and dangerous, and the mermaids must take it from Zac. Knowing this, Zac searches for the perfect hiding place and decides on an old warehouse.
The Trident is every bit as powerful as Zac imagined. Only, he can't get it to work! Zac wonders if the Trident needs to be activated by moonlight and breaks into Rita's secret Grotto.
Will pushes himself too far when Zane challenges him to prove his skills as a free-diver. The girls discover a unique crystal in the rock from the Moon Pool.
Kim attempts to derail Don and Samantha's wedding. Lewis receives an opportunity to study in America. Cleo realises she's got to let Lewis live his own life and let him go overseas.