Sophie and Ryan damage the Moon Pool in their efforts to obtain the rare crystals. The girls improvise and use their own magic to prevent the impact of the comet and a planet wide catastrophe. Rikki, Cleo and Bella graduate with a surprise.

A unusual and rare planetary alingment is set to cause the full moon to remove a mermaids powers if they enter the moon pool! Charlotte shows immunity and tries to reveal the girls secret before Lewis takes her to Mako Island. The girls follow and a battle erupts. But who will win?

Dr. Denman sets up a trap for the girls at Mako Island and Zane is forced to decide who he should be helping.

More friction arises, this time over Lewis' birthday party. Charlotte takes control and drives Rikki away from the party. However, things go out of hand and it is up to her to save the day.

Miriam is having a pool party and Cleo considers going despite the risks of being around water. Meanwhile, Emma contemplates her future as a swimmer and Rikki makes a new discovery.

In need of cash, Rikki decides to go and searching for a lost statue with a huge reward. But she lies to Emma and Cleo, which causes danger when Rikki is knocked out!

Charlotte's stubborn nature and thirst for knowledge leads her to Max, who confirms her suspicions and leads her to the Moon Pool. Lewis meanwhile is having trouble trying to keep their relationship together.

Zane is curious by Rikki's reluctancy to reveal where she lives. So one day, he eventually convinces her to reveal her home: a trailer park with her grouchy father.

Emma has to take Eliot for horse riding lessons and the competitive perfectionist tries to be better than the instructor. Meanwhile, Lewis double dates with Charlotte and Cleo.

Lewis is offered a great job with a marine biologist, but the girls are concerned that his interest will cause him to reveal too much information

Charlotte demands answers to why Lewis is hanging out with the girls so much. She starts to believe an excuse from Cleo, but then a discovery from inside Max's research brings her to the secret! Meanwhile, Ash decides to help Emma with her "fear of water"

It's time for Emma's family's annual vacation trip, but she can't go as the risks are too high. But all her excuses don't go very well with her family. Meanwhile, with the return of Dr. Denman, Zane is closer than ever to cracking the girl's secret.

Don gets a second job at the Marine Park on the Pirate ship and outshines Cleo, threatening the future of her Dolphin show. Bella and Will find difficulty trying to connect with each others' interests.

Everyone is shocked when Cleo is fired at the Ice Cream Stand, and even more so when Lewis takes her place! Rikki and Emma strike back at him but end up going too far

The girls sit their final school exams and have to avoid a water attack in public when the full moon rises early. They confront the water force in the Moon Pool and are given a message about Mako Island.

Angry over the short friendship with the girls, Charlotte forces Lewis to choose between her and his friends. This results in Cleo to feel isolated and she runs away and gets lost. When he is informed, Lewis must make up his mind: Cleo or Charlotte?

Rikki receives counterfeit money at the cafe and is held captive by criminals on a boat. Bella and Cleo are forced to reveal the trio's secret to Will so they can rescue Rikki together.

Bella's eager to ask Will to the end of year party until she sees him asking Rikki. A big misunderstanding occurs which prompts Will to express his true feelings for Bella. Sophie tries to get Zane to change the name of the cafe.

Rikki, Emma and Cleo discover that sea turtles are being captured by fishing nets. When Rikki and Emma attempt to rescue the turtles by cutting the nets, it causes the fisherman to think that there is a rogue shark roaming their ocean.

Emma decides that she is not going to have her annual sleepover party due to what has happened to them. But Rikki and Cleo try to convince her otherwise. Meanwhile, Lewis conducts experiments on the girls.

The girls decide that they should accept Charlotte, and the four work together when they need to join the volleyball team to avoid failing Physical Education.

The girls have to fake sick as a result of a thunderstorm, so their secret won't be discovered at school. But their 'sickness' attracts the attention of doctors.

Cleo's sister Kim finds her diary and thinks that Cleo and her friends are 'evil mermaids' and she plans to tell everyone. Meanwhile, Lewis goes to Mako Island to find out more about what happened to the girls.

With Will finding out about Mako Island, Bella tries to misdirect his search so that he will not discover the Moon Pool. However, Lewis and the girls find out that the Moon Pool is different.

Zane learns of the myth of Ambergris, a fragrance that can make mermaids fall for any man that wears it. When he buys it, Nate ends up wearing it and Emma, Cleo and Rikki all fall for him!

Cleo's family and Sam go on a picnic to the beach, which leads to tension when Cleo refuses to go near the water. Kim abuses the fact that her father is happy in order to get lots of gifts. Will's sister Sophie competes with Bella to get the job Bella wanted at Rikki's Cafe.

Cleo has to put off Lewis' romance plans in order to help Kim with her crazy love life. Meanwhile, Don meets up with a National Parks Manager, Samantha, and the two decide to date.

On the night of a full moon, Lewis, Emma, Rikki and Charlotte accompany Cleo's family for a camping trip at Mako. When all three girls are affected by the moon, they are unable to stop the curious Charlotte...

Cleo decides to restart her friendship with Lewis and embrace her abilities, while Emma is shocked with the new supervisor who has big changes planned.

Emma gets poisioned after cutting her finger on some coral and she begins to turn into a white scaled monster! Meanwhile Charlotte thinks Cleo is trying to break her and Lewis apart.

The girls discover the Mako crystals contain immense energy and need to mount a rescue mission when Zane jealously steals one in an effort to gain Rikki‟s attention.

Bella tries to get close to Will but when Bella goes to his place she sees him with another girl. Meanwhile Lewis tries to test the water from the moon pool but gets caught by his teacher.

Lewis enters the annual fishing derby. When Cleo sees him struggling, she decides to help him out with disastorous consequnces. Meanwhile, Rikki and Zane are trapped on a hotel balcony.

Rumour has it that Cleo has a boyfriend and her friends and family are trying to find out who he is. Meanwhile, Zane continues his search for the 'sea monster' he saw.

It's full moon and the girls insist that they don't need Lewis to assit his help as all three girls are staying at Emma's and Ash is coming over. When Cleo and Rikki fall under the moon spell, can Lewis stop them from revealing their secret to Ash?

Bella helps Will with his free-diving training but when she realises he's more interested in her as a mermaid than a girl, she's hurt. Rikki and Cleo have to improvise when the cafe's first corporate function is actually a children‟s party.

Cleo and Kim are stuck with their cousin Angela who wants to go body boarding and causes a bird brained distraction when Cleo refuses.

The girls have problems with their new powers and Cleo finds that Lewis isn't helping. A new girl called Charlotte arrives and develops a crush on a certain charecter

With Cleo's parents now divorced, Cleo is ordered by her dad to take more care of Kim, starting with taking her to a concert. But on the night, Cleo, Rikki and Emma all accidentally see the full moon, and take off to Mako Island, with Lewis in hot pursuit. Once there, the girls undergo another magical transformation in the Moon Pool, as a rare planetary alignment intensifies the power of the full moon – Emma's power is enhanced so that she can produce snow and frost, Rikki can conjure lightning, and Cleo can now control wind as well as water. After the moonstruck girls nearly harm Lewis, they realise that they must work to control their new powers, before anyone else gets hurt.

Rikki is offered a job to collect rare fish. At first it seems perfectly fine, until she finds out the person that hired her is selling the fish for large profits.

Cleo's 16th birthday is approaching and she thinks that her father is going to throw another embarrasing birthday party. Meanwhile, Zane tries to find the 'sea monster' that he saw when he almost drowned.

The full moon gives Cleo a power to put guys in a 'trance' and she suddenly gets a rush of admirers.

Three very different teenage girls, Emma, Cleo and Rikki, facing everyday teenage problems. With a twist: they're mermaids; after discovering a magic place where they are given incredible powers over water that change their lives forever.

Emma is doing well at her new job at the JuiceNet cafe, but when she is left in charge, she has trouble managing her new employee, Rikki.

Lewis is puzzled when he dreams about Cleo being photographed by people. Later, he and Cleo take Eliot and Kim to the marine park. Meanwhile, Emma thinks something is up between Ash and Rikki.

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.