List of H2O: Just Add Water episodes

The following is an episode list for the Australian television show H₂O: Just Add Water, which airs on Network Ten, Disney Channel Australia, Nickelodeon, Nickelodeon UK and other television networks worldwide. Series one premiered in Australia on 7 July 2006, and series two began there on 28 September 2007. The third series premiered in the United Kingdom on 26 October 2009, while its Australian premiere is not expected until early 2010.

Series overview

Series		Episodes	Originally Aired		DVD Release
			Series premiere	Series finale	Volume 1	Volume 2	Volume 3	Volume 4	Volume 5	Volume 6
	1	26	7 July 2006 (2006-07-07)	29 December 2006 (2006-12-29)	12 September 2006 (2006-09-12)	12 September 2007 (2007-09-12)	5 March 2008 (2008-03-05)	7 May 2008 (2008-05-07)	7 July 2008 (2008-07-07)	5 November 2008 (2008-11-05)
	2	26	28 September 2007 (2007-09-28)	21 March 2008 (2008-03-21)	27 January 2009 (2009-01-27)	2 June 2009 (2009-06-02)	2 September 2009 (2009-09-02)	—	—	—
	3	26	26 October 2009 (2009-10-26) (UK)	TBA	TBA	TBA	TBA	TBA	TBA	TBA

Episode list

Series one: 2006

Three girls—Emma Gilbert (Claire Holt), Cleo Sertori (Phoebe Tonkin) and Rikki Chadwick (Cariba Heine)—accidentally find themselves on Mako Island, where the full moon transforms them into mermaids when they enter a pool of water. They discover their amazing powers over water: Cleo can control the shape and volume of water, Emma can freeze it, and Rikki can boil it. Lewis McCartney (Angus McLaren), a friend of the girls, helps them avoid being exposed. The series mainly focuses on the girls learning to control their powers properly, finding love, and dealing with everyday problems like as siblings and accidental contact with water. Cleo meets a former mermaid, Louise Chatham (Christine Amor), who reveals to the girls how they became mermaids. After Zane Bennett (Burgess Abernethy) becomes trapped on Miss Chatham's sinking boat, Emma rushes to save him, accidentally revealing her tail and causing Zane to begin searching for this "sea monster". At the same time, he and Rikki become a couple. At the conclusion of this series, Zane helps Dr. Denman (Lara Cox) to capture the mermaids without knowing their identity. When he realises what he's done, Zane works with Lewis to release the girls, who trick the scientists into believing they've given up their powers to the lunar eclipse while they have actually only been removed for twelve hours.

Episode	Title	Director	Original airdate	Production code
01	"Metamorphosis"	Colin Budds	7 July 2006 (2006-07-07)	101
Three girls—Emma Gilbert, her friend Cleo Sertori, and Rikki Chadwick—find themselves stranded on Mako Island and seemingly trapped in an underground cavern. They manage to escape through a moonlit pool of water connected to the ocean. The girls are later found by the water police. The following day, the girls realise they are no longer the same: they become mermaids every time they come into contact with water. In addition, Cleo and Emma discover they have unique powers over water. Cleo can control its shape and volume, and Emma can freeze it. Rikki concludes she lacks a power after several failed attempts. All three girls understand that this experience will change their lives and friendship forever.
02	"Pool Party"	Colin Budds	14 July 2006 (2006-07-14)	102
Despite the risk involved, the desire to attend Miriam's pool party is too strong for Cleo. Rikki discovers she does indeed have a power at the JuiceNet Café: the ability to boil water. While at Miriam's party, the prankster Zane Bennett and his friends toss Cleo into the pool, while Lewis arrives on the scene just in time to discover Cleo's secret. Emma and Rikki arrive soon after; Emma freezes the door locked so no one can come out and see Cleo as a mermaid, and Rikki evaporates the water off Cleo's tail so she returns to normal. The girls have gained an ally in Lewis, who swears he will never tell of their secret. Meanwhile, Emma is upset because she's a mermaid now, so she leaves every swimming training for the first time, causing her parents to be concerned about it. In the end, Emma decides to leave the swimming team which makes her parents very worried.
03	"Catch of the Day"	Colin Budds	21 July 2006 (2006-07-21)	103
Cleo does not share her friends' enthusiasm for their new-found abilities. Rikki and Emma make efforts to free young sea turtles from fishing nets, only to cause a media frenzy of sharks patrolling the waters. Believing her father to be involved with illegally catching the turtles, Cleo goes after one of his boats – but finds herself caught in a net. Rikki and Emma save her, and Cleo discovers it was her father's workers, not her father himself, catching the turtles. The episode closes with the girls running into the ocean, and with Cleo showing her friends she can swim and hold her breath.
04	"Party Girls"	Colin Budds	28 July 2006 (2006-07-28)	104
Emma travels back to Mako Island where she finds a mysterious locket at the bottom of the moon pool. The risks associated with Cleo's new job at the marine park give her friends cause for concern but Cleo's determination to lead a normal life helps convince Emma to set aside her own concerns and go ahead with her annual sleepover party. Lewis tries to check what bottles don't have a water. Miss Chatham makes her first appearance by giving hints to Cleo about her mermaidness when Cleo got splashed by one of the fish that were supposed to be fed to the dolphins. Miriam is upset because she wasn't invited to the sleepover. Zane comes with a plan and they invite themselves to the party. All of the girls (except Cleo, Emma and Rikki) begin talk with Zane and this makes the party boring. Emma and Rikki evict Zane from the sleepover party and Miriam is surprised to see Emma's locket, so she wants it. Cleo accidentally touches water, but runs and hides herself in a closet. When the guests open the closet door, Cleo has already zipped herself up in a sleeping bag. She prevents others from feeling her tail by making the drinks explode, just as Miriam was about to steal Emma's locket. Rikki catches Miriam with the locket, takes it back, and gives it to Emma, who in return gives it to Cleo. She does this based on the belief that a mermaid who can hide her tail so well can surely take good care of so valuable a locket.
05	"Something Fishy"	Colin Budds	4 August 2006 (2006-08-04)	105
Cleo's secret diary falls into her sister Kim's hands. Kim grows suspicious when she reads that Cleo and her friends are mermaids and shares her ideas with Elliott, whose initial scorn turns to belief when Emma accidentally freezes his shower. Rikki, Emma, and Lewis quickly turn the kids' suspicions to Miriam, who Kim thinks is the leader of the pack. Kim and Elliott plan to expose the girls at the Miss Sea Queen pageant. Cleo, who is on stage, uses her power to repel the water while the other girls' costumes—including Miriam's—are ruined. Cleo convinces Kim the diary was for an English project, and to keep anyone from finding it again submerges it in the moon pool. Meanwhile, Lewis goes to Mako Island to analyse the moon pool to find out that how the girls became mermaids.
06	"Young Love"	Colin Budds	11 August 2006 (2006-08-11)	106
In an attempt to show off, Elliot goes surfing and nearly loses his life; Rikki is forced to save him, despite the risks involved with her secret, and ends up with Elliot developing a crush on her. The girls turn to Lewis for advice when the crush gets out of hand but the abrasive Rikki has a hard time letting him down gently, resulting in him running away. When Rikki finds him to apologise, however, she risks revealing the mermaid secret to him by almost being locked in a green house that was about to water the plants. Cleo, Emma and Lewis come to the rescue. Rikki and Elliot become friends.
07	"Moon Spell"	Colin Budds	18 August 2006 (2006-08-18)	107
Miss Chatham forewarns Cleo to not look at the full moon, but the girls scorn her warning on the basis that they are mermaids, not werewolves. Emma throws a birthday party for her dad, but forgets everything and loses her inhibitions when a full moon strikes and she sees its reflection in a bowl of punch. She is unusually rude to the guests and devours all the food prepared for the party when her friends try to hide her from the guests. Additionally, her mermaid tail will not go away after she touches water; however, when the full moon goes down, the tail vanishes along with Emma's memory of what happened that night. The girls learn that the full moon is a true danger to them and begin wondering who this mysterious Miss Chatham truly is. In the end, Byron tells Emma she kissed him in two times last night (Emma kissed Byron in two times while being affected by the moon) and she starts wonder what he's talking about.
08	"The Denman Affair"	Colin Budds	25 August 2006 (2006-08-25)	108
The girls reluctantly agree to let Lewis get a research assistant's position with a marine biologist, Dr. Linda Denman, hoping to determine what's behind their transformation. They are concerned when Cleo notices Lewis has a crush on Dr. Denman. Lewis forgets a DNA sample from Cleo, which is discovered by Dr. Denman. She realises the sample is not what Lewis claimed it was, and offers him a lucrative job. He must decide what it is he wants: money, or loyalty to the girls. Cleo finds out Dr. Denman created the article about the sample. Dr. Denman is going to leave and asks Lewis to come along. The next day, when Dr. Denman leaves, Lewis doesn't leave, takes the sample and deletes the article.
09	"Dangerous Waters"	Colin Budds	1 September 2006 (2006-09-01)	109
One of Cleo's fish has died. Rikki, in the attempt to make up for her brusqueness, tries to find her a replacement fish. She uses her mermaidness to her advantage by diving where no fish collector can dive and picking out a fish that strongly resembles Cleo's lost one. She meets a man who offers her to pay her well if she sells him fish like the one she was bringing to Cleo. Rikki agrees, believing that the man is what he says he is (a marine park breeder of rare fish), but when she learns the man who hired her is lying and actually is selling the fish illegally to earn large profits, she takes it upon herself to get revenge and deliver him to the authorities. Rikki uses her powers to attack the man, but Cleo and Emma stop her.
10	"The Camera Never Lies"	Colin Budds	8 September 2006 (2006-09-08)	110
A short film contest on the subject of heroes captures the focus of the girls' attention, but a film about Emma's mother is not Rikki's idea of fun and she decides to use her abilities to capture some impressive underwater footage of sharks. Ineligible to compete himself as his father is on the judging panel, Zane recruits Lewis to document a recreation of his father's famous windsurfing trip to Mako Island and gets trapped by sharks on the shore. Luckily, Rikki was also there filming her "masterpiece" and manages to scare the sharks away with her powers. Rikki quits from the contest because she has to explain from where she shot the film. Emma also quits because her mother said she rescued Zane's father from drowning.
11	"Sink or Swim"	Colin Budds	15 September 2006 (2006-09-15)	111
Byron asks Emma for training help prior to the school swimming meet. After initially turning him down, she changes her mind but becomes a "heavy training dragon", to Byron's disappointment. Lewis continues his experiments on the girls but Rikki does not like being treated like a specimen and does her best to disrupt his research. Emma and Byron end up kissing, but Emma dumps Byron, believing that coaches should not be involved with their students. It turns out that Byron is challenging Zane; though Emma swore she wouldn't attend the race, she comes anyway and watches Byron beat Zane in the race. After the victory, Emma and Byron become friends.
12	"The Siren Effect"	Colin Budds	22 September 2006 (2006-09-22)	112
Another full moon approaches. Before nightfall, Rikki enters Cleo up for a karaoke contest, not realising that she has no ability to sing and Cleo embarrasses herself in front of everybody listening. That night, Lewis and the mermaids sleep at Cleo's house to try avoiding the full moon; while in the bathroom Cleo glimpses the full moon in a reflection, touches the water bearing it and is suddenly able to sing better than any other girl in town. Lewis realises she's become a siren, one of those ancient, mythological mermaids whose voices lured sailors to their deaths. Cleo hypnotizes Lewis with the siren song and they kiss. Emma, Rikki and Cleo's father see this and Cleo's father takes Lewis out. As with Emma's experience, Cleo's unstoppable under the moon and manages to get her voice on radio. In the morning, Cleo, to her father's irritation, escapes to the JuiceNet café and sings in front of all the town's boys; the full moon sinks, causing Cleo's wonderful voice to go with it, along with her brief burst of popularity. In the end, Cleo meets up with Lewis and says that they are only friends, but they have strange feelings.
13	"Shipwrecked"	Colin Budds	28 September 2006 (2006-09-28)	113
When Zane causes the enigmatic Miss Chatham to be evicted from her boat, Emma invites her to stay at her home. Overhearing her concern for her "treasure", Zane chases after Miss Chatham seeking compensation for his damaged jet ski when she departs the marina in her boat. Zane attacks Miss Chatham and she passes out. Emma and Lewis arrive in time to help with a medical emergency but when Zane gets trapped on the sinking boat, Emma must risk being seen as a mermaid to save him. Emma uses her tail to break open the boat's door, and Zane sees her tail. After he passes out, Emma takes him to Mako Island, where he wakes up and makes a vow to find out what it was that saved him. Emma gives Miss Chatham her treasure, which is a locket. Miss Chatham moves to a retirement home.
14	"Surprise!"	Jeffrey Walker	6 October 2006 (2006-10-06)	114
Cleo is counting the days until her sixteenth birthday, fully aware that her big day can only be ruined by one thing: another one of her father's embarrassing birthday parties. Zane embarks on a hunt for the "sea monster" he saw when he nearly drowned and recruits Lewis to help, but Lewis has promised the girls to do everything he can to keep Zane well away from them and Mako Island. Cleo is upset when her father throws her a party and escapes to Mako Island, but Lewis and Zane are there. Lewis spots Cleo and tries to stop Zane from seeing her as a mermaid. Lewis and the others have a party at the JuiceNet café for Cleo.
15	"The Big Chill"	Jeffrey Walker	13 October 2006 (2006-10-13)	115
Emma is excelling at her new job at the JuiceNet café, but when Wilfred leaves her in charge for an entire weekend, her no-nonsense managerial style puts her at odds with her newest employee: Rikki. When Zane and Miriam come into the café for a drink, Rikki brings Miriam the wrong drink, and after Miriam becomes irritable, Rikki quits the café. In retaliation, Miriam sneaks into the café's freezer and turns the temperature up. Emma arrives, and upon noticing the freezer open and warming up, uses her powers to freeze the contents, which includes Miriam, who has hidden inside. Despite the animosity between Rikki and Emma, the girls work together - Rikki slowly melts the ice while Cleo gets the bodily fluids moving - before Wilfred returns. After saving Miriam, Wilfred is going to fire Emma, but Rikki becomes rude to be fired and giving Emma her job back.
16	"Lovesick"	Jeffrey Walker	20 October 2006 (2006-10-20)	116
Cleo attracts the attention of a new dolphin at the marine park. Zane Bennett, in his attempt to find out what "monster" saved him, convinces Cleo that he needs the marine park's library in order to learn more about dying species of wild sea creatures. Cleo's friends and family mistakenly believe that Cleo is calling a boyfriend when speaking with Zane; when Mr. Sertori grounds Cleo, Kim eavesdrops on her sister while she's speaking on the phone and draws the conclusion that Cleo's going to elope. Lewis, Emma, Rikki, and the Sertoris come just as Zane and Cleo are kneeling in front of a marine park manager, learning about dolphins' habits, and learn that Cleo had only been trying to help a sick dolphin.
17	"Under the Weather"	Jeffrey Walker	27 October 2006 (2006-10-27)	117
A sudden thunderstorm forces the girls to fake illness to stay home from school or risk their tails growing in front of Emma's mom. Doctors believe this is a "rare topical disease" when Rikki gives the girls red blotches and high temperatures before Emma gives them low temperatures. Arrived with Cleo's parents to visit the girls, Kim suspects that the girls are faking it but has no proof until the girls are about to be taken to the hospital; Emma lies and says they had pretended to be sick so they could avoid a biology test. Doctors say the only one who's sick is Elliot because he has measles. Kim also has the measles.
18	"Bad Moon Rising"	Jeffrey Walker	3 November 2006 (2006-11-03)	118
Yet another full moon is approaching. Haunted by his encounter with the "sea monster", Zane steps up his investigation, which leads him to Mako Island. Rikki catches a glimpse of the full moon's reflection, causing her to lose control of her power. Rikki escapes Emma's house to go to Mako Island, and later Zane arrives when he sees fire. After they find each other on the island, Rikki kisses Zane, causing him to pass out from dehydration. Emma, Cleo and Lewis followed Rikki to Mako and find her sitting beside Zane, who has no memory of that day's events. Rikki is taken to the moon pool, where the moon finally leaves the sky and Rikki realises that for the first time, she saw the full moon and she's not invulnerable to its attacks. The next morning Zane confronts Rikki about the kiss in front of Cleo, but having no memory of it Rikki tells Zane to forget about it.
19	"Hurricane Angela"	Jeffrey Walker	10 November 2006 (2006-11-10)	119
The arrival of Cleo's cousin Angela is seen by the girl's father as an opportunity for Cleo to learn some maturity and responsibility. However, chaperoning a headstrong girl with a fondness for water quickly brings on its challenges - especially when the girls find they have stolen possessions, a lost cousin and a pelican in their house. Cleo accuses Kim for the pelican. When Cleo gives the pelican back, she's accused for the pelican. The pelican is soon revealed to not from the marine park. Angela is finally found. It is soon discovered Angela stolen the pelican to make Cleo and Kim fighting, only to go for body boarding. In the end, Cleo buys the MP3 player and gives it to Kim. Cleo and Kim end the argument. Kim asks Cleo where she bought the MP3 player only to return it because she less like the blue colour. This forces Cleo and Kim argue again.
20	"Hook, Line and Sinker"	Jeffrey Walker	17 November 2006 (2006-11-17)	120
The annual fishing derby has arrived, which the eager Lewis has entered in the hopes of winning with his quirky new lure. Cleo, who knows this lure cannot attract fish, intervenes by purposely placing a deep-water tuna on his line; rather than securing Lewis's victory, Mr. Sertori, the judge, believes Lewis to be a cheater and disqualifies him. Meanwhile, Rikki attends a seminar where she runs into Zane. The pair gets locked up in the Bennett's balcony when the door gets shut; they have no choice but to speak with one another; they realise they have feelings for one another. Cleo rectifies her error by enlisting Emma to help her place large fish on the other contestants' lines, which results in Mr. Sertori allowing Lewis back into the competition and announcing him as the winner.
21	"Red Herring"	Jeffrey Walker	24 November 2006 (2006-11-24)	121
An innocent comment about her dependable nature convinces Emma she needs a change, so she decides to colour her hair red. The girls discover that as dying hair involves water, resulting to mermaid transformation, Emma only has red hair when she has her tail. Zane's sea monster investigation leads him to Miss Chatham who he's convinced is at the centre of the mystery. When trying to find more research on the "monster", Zane gets Nate to help him inspect Miss Chatham's (sunken) boat, near Mako Island. After spotting sharks, Nate returns to the boat, but Zane spots a mermaid with red hair leaving Miss Chatham's boat; this was Emma fetching pictures of Miss Chatham with her mermaid friends, in mermaid form, before Zane could look around the boat and possibly stumble upon them. Zane returns to the JuiceNet cafe, and tells what he saw; to everyone's disbelief. Afterwards, Rikki tracks Zane down and agrees to go out with him as long as he stops his mermaid hunt.
22	"Fish Out of Water"	Jeffrey Walker	1 December 2006 (2006-12-01)	122
When at the cinema, Cleo and Emma spot Zane and Rikki on a date and find out that they are going out. Concerned that Zane will find out their secret, Emma gives Rikki an ultimatum: her and Cleo, or Zane. Rikki believes "friends don't give friends ultimatums" and refuses to choose. Zane's father, Harrison Bennett, throws a lunch where he unveils his plans to develop Mako Island. Emma and her parents are guests, as well as Rikki, as Zane's date. Feelings realign between friends as Emma joins Rikki's vocal opposition to the plans, and Zane once again takes a stand against his father, causing the Mako-renovation plans to be destroyed.
23	"In Too Deep"	Jeffrey Walker	8 December 2006 (2006-12-08)	123
History may be repeating itself as Rikki's ability to keep the girls' secret is tested when she discovers a locket almost identical to Miss Chatham's in a jeweler's shop. Miriam, a sworn enemy of Rikki, discovers Rikki's longing for the locket and purchases it first to get under Rikki's skin. While Zane tries to persuade Miriam to give it up, Miss Chatham recounts to the girls the story of her teen years. Her friend Julia, who was nearly identical to Rikki in personality and disposition, made a mistake Rikki seems close to making – she told her wealthy boyfriend she was a mermaid, only to have him betray her. Zane manages to acquire the locket, and gives it to Rikki. Rikki assures her relieved friends that she would never tell their secret to Zane.
24	"Love Potion #9"	Jeffrey Walker	15 December 2006 (2006-12-15)	124
Lewis and Miss Chatham are arguing what will help the girls: Magic or science. With the school dance approaching, Emma and Cleo are fretting about having to ask Byron and Lewis to go with them, relying on the boys to make the first move. But Byron does not ask Emma, who he thinks is too busy heading up the organising committee, and Lewis is too caught up in his work on a new scientific way to make it easier for the girls to be mermaids, by making them waterproof; however, the formula backfires and makes the girls redden, forcing them to leave the dance or risk humiliation. The girls go to Mako Island, to the underground cavern where they became mermaids. Lewis leaves the party, to head to Mako Island, and encounters Miss Chatham on the pier. She convinces him that science can't explain everything, and that maybe he should just be there for the girls. After Lewis arrives at the underground cavern, he apologises about the side-effect. The girls lament about missing the dance, and Lewis tells Emma that Byron is still at the dance. Emma says that if Byron asked Miriam to the dance, he would feel honour-bound to walk her home. Lewis reveals that Miriam had asked Byron, not the other way around. Emma dives in the underground pool, racing back to the dance. Rikki then believes Miriam must have gotten her "claws" into Zane, but Lewis says Zane had asked his "mates" to keep her away from him, and that he's still waiting for her (Rikki). Rikki then follows Emma's lead, and dives into the pool, to return to the dance. Lewis admits to Cleo he'd forgotten about the dance and apologises. Cleo says the only reason she went with Nate was because no one else had asked her. Cleo admits that she's interested in Lewis, who starts to analyze why. He then decides to stop analyzing it, and just go with the "magic". They share a kiss and become a couple.
25	"Dr Danger"	Jeffrey Walker	22 December 2006 (2006-12-22)	125
Emma's family is planning a trip to a resort where Emma will have to go swimming, so she has no choice but to refuse to go - which irritates her parents and causes animosity between them. The return of marine biologist Dr Denman concerns Lewis and the girls but Zane sees a possible ally (or worse, a competitor) in the search for his mermaid and approaches her for help. Dr. Denman finds one of Cleo's scales from her tail and realises it's identical to the one Lewis left behind awhile before in her lab (see episode 8). She also finds the heart Lewis carved into the sand by the moon pool and makes the connection, realising the owner of the scale is no ordinary fish. She attempts to badger information out of Lewis, thoroughly convinced that Lewis is strongly connected to the scale she found, while feeding wrong information to Zane, leading him to believe that she is approaching information on the mermaid Zane is positive he saw. Rikki accidentally tips Zane off to Dr. Denman's thoughts on the discoveries near Mako Island. Zane brings up the topic of mermaids, which grows into a fierce argument and Zane yelling at Rikki to never see him again. Meanwhile, Dr. Denman sets up underwater cameras and detectors, leading to photos of the mermaids while swimming. Dr. Denman gets perilously close to the secret while the girls try frantically to hide their secret and not allow the scientists to expose them. Their efforts are in vain; when Mr. Bennett, Zane's father, finds a picture of the girls with their faces - and tails! - the scientists are bent on finding them, capturing them and will not give up.
26	"A Twist in the Tail"	Jeffrey Walker	29 December 2006 (2006-12-29)	126
The hunt for the now identified mermaids intensifies as Dr Denman sets a trap for Cleo, Emma, and Rikki at Mako Island, then forcing Zane to make a decision about where his loyalties lie: with his father or with Rikki. A lunar eclipse also gives the girls an opportunity to free themselves from further pursuit by losing their powers. While they are led to believe this is permanent, they eventually discover that the effects of the lunar eclipse only lasts for twelve hours and they get their powers back. Rikki and Zane break up, but they remain friends.

Series two: 2007–2008

The girls discover their new powers after being affected by a special full moon. A new girl named Charlotte (Brittany Byrnes) appears, who develops an instant crush on Lewis. Cleo breaks up with Lewis because he gets too clingy and protective of her, and he starts dating Charlotte when she tricks him into kissing her. Emma meets Ash (Craig Horner) and flirts with him, but makes him frustrated with secrets she won't tell him, so she reveals to Ash she's a mermaid. Rikki and Zane get back together. Meanwhile, Lewis meets Max Hamilton (Martin Vaughan) and from him learns more about Mako Island. After discovering her grandmother was a mermaid, Charlotte meets Max who knew her grandmother, one of the original mermaids, and becomes one as well. She and the girls become sworn enemies, resulting in Charlotte losing her powers and Lewis being with Cleo once more. The series ends with the girls running to the ocean and turning into mermaids as their boyfriends look on.

Episode	Title	Original airdate	Production code
27	"Stormy Weather"	28 September 2007 (2007-09-28)	201
It's the night of a full moon, and all three girls accidentally see it when they open Emma's door. Under its spell, they swim to Mako Island, with Lewis in pursuit. The moon pool enhances their powers due to a special planetary alignment. Rikki is now able to control lightning and fire; Emma can freeze anything without water, create blizzards and control the clouds(in a form of weather control); and Cleo can control air currents and wind. Under the spell of the moon, together they create a powerful electric storm and blow Lewis away. The next day, the girls are surprised when they discover their new powers. Upon arriving at Mako Island, they find a soaking-wet Lewis, who explains everything to them. The girls must work to control these new abilities. Meanwhile, Cleo's parents have divorced, and Cleo is outraged when her father says she must start watching over her sister Kim, starting with a concert.
28	"Control"	5 October 2007 (2007-10-05)	202
The new girl at school, Charlotte, gets splashed when Cleo tries to control the school sprinkler. Charlotte instantly develops a crush on Lewis when she sees him, creating a new rival for Cleo. Lewis has little success when he decides to test the girls' new and unpredictable powers; Rikki lights his plastic shark on fire, Emma explodes the fake penguin, and Cleo accidentally knocks Lewis into the moon pool. Emma helps her brother Elliot deal with a meddlesome team-mate, despite her telling the others to control their powers. Lewis' constant attention drives Cleo crazy, leading her to dump him and become only friends. The artistic Charlotte's "small and precise" brush strokes with her Japanese painting leads Lewis to help the girls in controlling their powers better.
29	"The One That Got Away"	12 October 2007 (2007-10-12)	203
Zane's reappearance forces Rikki to decide if staying away from him is what she really wants. Can Rikki become involved with Zane again and still keep her secret? As Lewis' new friendship with Charlotte grows to Cleo's dismay, so do Cleo's suspicions about her, but she insists it has nothing to do with jealousy. Cleo continuously embarrasses herself when she falsely accuses Charlotte of several things both privately and publicly, such as Charlotte having a boyfriend called RJ or Charlotte setting her old school's art room on fire. Rikki decides to tell Zane about her secret at the pier, but the impatient Nate sprays her with water first. Zane helps Rikki escape and discovers her secret. They become a couple again, under the condition that neither of them tell Cleo or Emma.
30	"Fire and Ice"	19 October 2007 (2007-10-19)	204
With Emma's parents away for the weekend, Rikki comes over to stay but her behaviour rubs off on Emma, who decides to prove that she too can be a rebel. But is she trying too hard? And can she handle the consequences that come with throwing a party? Lewis tries to become more manly when Nate tells him it may have been why Cleo broke up with him. So he agrees to let Nate teach him karate. Cleo gets chocolates and flowers sent to her from a secret admirer; she thinks it is Lewis, but it's really Nate. At Emma's party, Nate tries to kiss Cleo. Lewis angrily realizes what happened and fights Nate. The Gilberts return and conclude the party is Rikki's fault, but Emma owns up to what she has done.
31	"Hocus Pocus"	26 October 2007 (2007-10-26)	205
When Lewis presents the girls with a rare book he discovered about mermaid mythology, Rikki and Emma reluctantly agree to help Lewis and Cleo make a potion that will give the girls the power to grant wishes. For Cleo it's an opportunity to reunite her fractured family, but when the project grows out of control (Rikki heated it), they must act quickly to clean up the café before Wilfred arrives to shoot a commercial. Lewis' book is swallowed by the project. Wilfred and Charlotte arrive and the girls and Lewis have to do something. Emma and Rikki distract Wilfred and Charlotte, while Cleo and Lewis use the piece of the project which she taken to make her family's wishes. In the end, Cleo figures out her father didn't wish to have his wife back. Mr. Sertori tells Cleo she can visit her mother.
32	"Pressure Cooker"	2 November 2007 (2007-11-02)	206
Cleo becomes concerned with Lewis spending time with Charlotte. Lewis insists things between them aren't as they appear, but perhaps he needs to tell that to Charlotte, who is convinced that he's not over Cleo. To make matters worse, Cleo's dad has invited a woman over for dinner. And just when it appears that welcoming a potential stepmother is the worst of Cleo's troubles, she meets her daughter...Charlotte! When Lewis comes over to convince Cleo that there is nothing going on between Charlotte and him, Charlotte keeps Lewis to herself with the help of her controlling mother and purposely asks Cleo if she could date Lewis, this upsets Cleo so she and Emma and Rikki use their powers to ruin Charlotte and Lewis' date. The next day, Lewis tries to tell Charlotte that he is not interested in her, but she says that she can wait, causing Cleo to gain a new enemy. Meanwhile, Cleo finds out Charlotte's mother was only spending the time with Cleo's father to grade his fish and decide whether or not to sell them at her restaurant.
33	"In Hot Water"	9 November 2007 (2007-11-09)	207
In need of money for a new computer, Lewis decides it is time he finds a job, and as luck would have it, a position becomes available at the aquarium when Cleo is fired. In an effort to help get Cleo her job back, Rikki and Emma set out to prove that serving ice-cream can be the hardest job in the world. But when the the aquarium's star attraction called Ronnie goes missing, Lewis becomes the prime suspect. Emma and Rikki feel they're the blame for Ronnie's disappearance. When Emma and Rikki fail the search, Lewis tells Cleo the blame are Emma and Rikki. Cleo yells at Emma and Rikki and they explain all to Cleo. The girls return Ronnie to aquarium. The boss apologizes to Lewis, and gives Cleo her job back.
34	"Wrong Side of the Tracks"	16 November 2007 (2007-11-16)	208
Rikki is embarrassed to tell her friends and Zane where she lives. When Nate and Zane are out riding, Nate steals a tag off someone's busted motorbike. Zane is seen when Nate drives off resulting in a huge rivalry. When Zane tries to return the badge the man comes out and thinks that he's stealing something else. Zane insults him without knowing that the man is Rikki's father! Without anyone knowing, Rikki watches through the window, and only sees Zane insulting her dad. Zane pressures Rikki to let him meet her father, but knowing that he insulted him, ignores him and tries to get away. After much persuasion Rikki takes him to where she lives. He has no problem with it but when he kisses her, her father catches him and throws him out. Meanwhile Cleo is dealing with a problem concerning Charlotte and Lewis' jacket, Charlotte asks Cleo to return Lewis' jacket to purposely upset Cleo, Lewis tries to convince Charlotte that they are only friends but she insists that he is wrong and will do anything to make Cleo jealous. In the end, Zane fixes Rikki's father's bike and they become good friends. Because of this, Rikki gives up from embarrassing and invites Cleo, Emma and Lewis to her house for a party. While at the party, Lewis gives Cleo his jacket after telling her that he only gave it to Charlotte because she asked him to.
35	"Riding for a Fall"	23 November 2007 (2007-11-23)	209
Emma is forced to take her brother Elliot for riding lessons by her mother. She gets jealous of the riding instructor Ash because he is better than her. Ash asks Emma to leave his horse Rebel to graze and warns her not to let the horse graze on the front yard because of weeds but Rebel does without her seeing. Rebel is poisoned and Emma helps him recover by using her powers. Meanwhile, Lewis is nominated for a prize and invites Cleo, but she thinks it is not a good idea since that they are only friends now, but with Charlotte desperate for wanting to go out with him she invites herself along leading to Lewis to lie to both girls.
36	"Missed the Boat"	30 November 2007 (2007-11-30)	210
Cleo fails the biology exam and she must study an entire weekend to correct it, which starts on Monday. Cleo must have a help in study, but the helper is Charlotte, not Lewis. While Cleo is studying, Charlotte asks Lewis to bring her to Mako Island to sketch the island. When Charlotte arrives to help Cleo, Cleo finds out Charlotte has given Cleo more homework, so she can spend more time with Lewis. Lewis and Charlotte arrive at Mako Island, but they're followed by the girls. Charlotte tries to make a move on Lewis but he tries to tell her that are only friends but is interrupted by Cleo who accidentally fell from a rock to the water and Charlotte hears. Lewis spots Cleo as a mermaid and stops Charlotte to see Cleo as a mermaid. Charlotte mistakes Lewis actions and kisses Lewis, which makes Cleo angry. The next day, Cleo finally took the exam, and passed. At the Juicenet cafe, Charlotte "makes" Cleo thank her for her tutoring, and Lewis tries to tell Cleo the truth but fed up with his relationship with Charlotte, Cleo tells Lewis he can do what ever he wants.
37	"In Over Our Heads"	7 December 2007 (2007-12-07)	211
Pressured by tight family finances and the promise of a big reward, Rikki agrees to help Zane search the ocean floor for a valuable lost statue. But she involves Emma and Cleo without telling them the full story about the reward money. The truth comes out, while Lewis reassures the girls that he will still be there for them, but when Emma calls Lewis on Cleo's phone, Charlotte sees and hang up. Annoyed at Rikki after they find out about the reward, Emma and Cleo go to the JuiceNet and bump into Lewis and Charlotte. Zane tells Rikki that she's tired and decides to give up from the mission, but she refuses and says she still has strength. Rikki finds a crate containing the artifact and uses a flotation device to lift it out of the water, but when the chain breaks, she finds herself alone in a dangerous situation when she is knocked unconscious with only Zane to help her. Emma receives a phone call from Zane saying that Rikki is breathing but not moving and they run off to help her, Lewis is about to go but Charlotte stops him saying that he is only meant to care for her now, fed up with her attitude Lewis tells Charlotte off and revives Rikki. Afterward Rikki reveals that her dad needed the money so that they could stay in town, and they're thinking of leaving for good. At a party at Rikki's, Lewis shows up with an envelope for Rikki containing the ten thousand dollar reward, but Rikki convinced that she doesn't take charity, declines. After much persuading on Zane's part she accepts the money and is able to stay in town. Emma, Rikki, Lewis and Zane hug, but Cleo doesn't join the hug because of Lewis dating with Charlotte.
38	"Fish Fever"	14 December 2007 (2007-12-14)	212
When the girls are searching for a coral for Cleo's fish, Emma finds a beautiful rainbow one, but she accidentally cuts herself on the coral. Emma starts eat fish food and acting weird. Cleo's fish is acting weird too. When Emma arrives to Marine Park to go swimming, a little girl sees her and tells that to her mum, but no one believes the girl. Cleo, Rikki and Lewis must bring Emma back home, but the problem is: Lewis has a date with Charlotte! While searching Lewis, Charlotte ends up bumping into Cleo and assumes Cleo is there to crash her and Lewis' date. After bringing Emma to home, Emma splashes herself in water, but as she turns into mermaid, the white scales appear. It's revealed the blame for white scales, eating fish food and acting weird is a coral!. Lewis brings Cleo's fish to biologist and the biologist creates the antidote. The antidote cures Cleo's fish. Lewis brings more antidote to help Emma, but she escaped. The search fail. Later that night when Emma's parents are having a romantic dinner, Emma comes back home and steals the lobster, so she eats it. Cleo, Rikki and Lewis arrive and see Emma as monster with white scales. Lewis splashes Emma with antidote and she returns to normal. In the end, Charlotte yells at Lewis for the destroyed date.
39	"Moonwalker"	21 December 2007 (2007-12-21)	213
The revived Sertori family camping holiday is ill-fated not just by choice of location, Mako Island, but in the unfortunate timing of coinciding with the full moon. Cleo's friends and Charlotte tag along to help one another stay out of trouble but Lewis' plans are soon tested. Later that night, Lewis and Charlotte go for a romantic walk. Discovered Charlotte's disappearance, Kim opens the "moonlight proof" tent, causing Cleo to get affected by the moon. Kim finds Lewis and Charlotte who almost kiss. Lewis takes Kim back to the camp, leaving Charlotte alone. Emma and Rikki eventually discover Cleo is gone. Despite Lewis' protests, they leave the tent and face the powers of the moon. Charlotte bumps into Cleo, she torments Cleo because she thinks Cleo is jealous of her new relationship with Lewis. Angry, Rikki and Emma who are watching nearby strike Charlotte with lightning, scared Charlotte runs away and finds the moon pool but at the height of the full moon may have unforeseen consequences. The girls defeat the power of moon and Emma freezes the moon pool so Charlotte can't become a mermaid. Lewis arrives and brings Charlotte back to the camp. The next day, the girls and Lewis have to find out Charlotte is a mermaid or not. Lewis "accidentally" splashes her with a drink to find out, but nothing happens, so Charlotte isn't a mermaid.
40	"Get Off My Tail"	28 December 2007 (2007-12-28)	214
After confiding in her that she misses spending time with Lewis, Cleo takes Rikki's advice to re-establish her friendship with him and to embrace her unique abilities; after all, Cleo is no ordinary girl, but Charlotte is. Cleo tries to spend as much time with Lewis as she can with out Charlotte in the picture to make him realize that she is the one for him, but Charlotte misunderstands this thinking that Cleo is just trying to make her jealous so she does the same. Meanwhile, when Wilfred leaves, he hires Ash as the current supervisor of the JuiceNet cafe which annoys Emma. Ash then decides to plan the big changes at the cafe. Emma is angry because Ash changed the menu, procedures and added the basketball to the cafe. Ash later accuses Emma for a mistake with the food and fires her. Later on, Ash wants Emma back again saying she's the best worker and without her the cafe will disappear. Ash then decides to take Emma to the movies.
41	"Irresistible"	4 January 2008 (2008-01-04)	215
Nate tries to convince Cleo's father of allowing him to take Cleo on a date by teaching Kim guitar lessons, but Cleo annoyed at Nate for following her all day threatens to call the police and say that he is stalking her. When he learns about myths considering ambergris, a substance which attracts mermaids, Zane seeks the help of Lewis. But Lewis thinks nothing of it (Zane tries to convince Lewis that he could use it to win Cleo back, but Lewis quickly ignores him not wanting Zane to know that he still has feelings for Cleo even though he is dating Charlotte) and leaves the bottle of ambergris Zane bought on the table outside the Juicenet Cafe, where Nate finds it and sprays it on himself. Everyone else in the cafe leaves because of the smell, but Emma since she is a mermaid reluctantly falls for Nate who is soon followed by Cleo and then Rikki (to Nate's enjoyment since he lusts for Cleo and loves the attention from girls). Lewis and Zane both jealous, try to talk some sense into the girls but they ignore them, then they follow Nate to the shore where he asks them to come along and swim. Lewis and Zane were looking for the girls and Ash tells them what had happened (who thinks that Emma does not like him so she hangs with Nate). When Lewis and Zane go to the shore, they find Cleo, Emma, and Rikki walking towards the water. Fortunately, the salt water washes Nate clean of ambergris; the girls regain their senses just as the water touches them. While Zane and Lewis distract Nate, the girls run off and keep Nate from seeing them. Lewis and Zane take the bottle and drown it. Emma apologizes Ash for "falling" for Nate.
42	"Double Trouble"	11 January 2008 (2008-01-11)	216
Lewis is troubled by a recurring dream about Cleo being discovered as a mermaid and Cleo saying that she misses him suggesting that he still cares for her. When Elliot asks Lewis for advice about girls, no one suspects he's planning on asking Kim Sertori out. Cleo and Lewis join the young couple on their first date to the water park and while it takes Elliot a bit longer to learn his lesson, the chaperons also come away a little wiser...and wetter. Cleo and Lewis realize that their friendship is strong and no relationship can stop that. Cleo gets splashed by water so she jumps into a show pool. Afraid his dream coming true, Lewis has to help her protect her secret; he does so by finding the orange bear Kim and claiming that's what looked like Cleo's orange tail, later Cleo thanks him and they have a very awkward intimate moment which is disrupted by Charlotte. Emma gets the wrong idea about Rikki's secret meetings with Ash, which were actually intended to give her an award.
43	"Moonstruck"	18 January 2008 (2008-01-18)	217
The full moon comes around again. When Ash has trouble asking Emma out, Cleo and Rikki prompt him to be firmer in his attempts to woo her. When the moon rises, Ash comes over with dinner; while opening the door, Cleo sees the moon. Rikki tries to take care of her while Emma talks with Ash. But moonstruck Cleo manages to get Rikki to see the moon; the two of them are determined to get Emma wet so Ash can see her in mermaid form. Cleo's attempts, though, are frozen by Emma so she cannot get wet. However, when Cleo forces her into a bathtub and makes her see the moon, Ash nearly sees her. It's only Lewis's quick timing that protects the girls' secret from Ash. The next day, not remembering anything, Emma tells Ash she really likes him and kisses him.
44	"The Heat is On"	25 January 2008 (2008-01-25)	218
Cleo throws a party for the girls' first anniversary as mermaids. But not all goes as planned when Zane accidentally knocks drinks on Emma, nearly revealing her secret to the people in the JuiceNet cafe. Emma misinterprets Zane's attempts to keep Ash from seeing her as a mermaid. When Ash and Zane get into a fight over the incident, so do Rikki and Emma, causing them to forget about the party and Cleo's preparations. Zane's and Ash's pool game make Emma and Rikki intervene and try to help the boys in winning; Emma for Ash, Rikki for Zane. When Rikki and Emma accidentally cause the beginning of a storm, they realize they missed the party, leave the cafe and reunite with Cleo at Mako Island. Cleo forgives her friends for the argument and they'll be best friends forever. Meanwhile, Lewis hurries to a picnic with Charlotte and they watch her favourite movie "Breakfast at Tiffany's".
45	"The Gracie Code (Part One)"	1 February 2008 (2008-02-01)	219
While looking research trying to uncover the secrets of the moon pool, Lewis uncovers the work of Max Hamilton, who fifty years earlier found himself in much the same role that Lewis is in now. Max realizes Cleo is one of the mermaids when he spots her locket - the very same one he made for Gracie, one of the original mermaids, fifty years ago. Lewis takes him the locket to get it fixed and Max reveals that he knows what Cleo is. Max tells Cleo and Lewis he created the lockets, loved Gracie, tried to discover Mako's secrets and being dumped by Gracie. When Cleo is out of earshot, Max tells Lewis that Cleo and Lewis should never have broken up because he "knows when people should be together". Lewis discovers a powerful ally in Max, who helps him continue on with his research. Charlotte is upset because Lewis now is avoiding her. Absent: Claire Holt as Emma Gilbert
46	"The Gracie Code (Part Two)"	8 February 2008 (2008-02-08)	220
Charlotte wants answers as to why Lewis is spending so much of his time with Cleo and the girls. Charlotte appears to be satisfied with Cleo's vague excuse that Lewis is helping them with a project, but her curiosity is piqued when, amongst Max's research papers, she spots an old photo of Gracie, her deceased grandmother. Lewis is tasked with finding out exactly what Charlotte knows about her grandmother, but Charlotte desperately convinces Cleo's sister to let her into the house and finds an old film of her grandmother - in mermaid form. The determined Charlotte will not let it go. Lewis "disbelives" it and explains this to the girls who order him to stop Charlotte. Meanwhile, Ash makes a well-intentioned attempt to help Emma overcome her apparent fear of water; just as Emma is about to show Ash her secret, she is interrupted and unable to show him what she wants him to see.
47	"And Then There Were Four"	15 February 2008 (2008-02-15)	221
Charlotte is determined to find out if Gracie, her grandmother, was truly a mermaid. Lewis, desperately trying to keep Charlotte from the girls' secret, returns the research to Max. But when Max meets Charlotte, he can't resist telling everything to the granddaughter of his once-lover. Charlotte knows everything, finds Mako Island, discovers the girls' secret, and becomes the fourth mermaid of the generation. Meanwhile, the girls have to stay at Cleo's to protect from the full moon, but Cleo struggles to tell her father to let Emma and Rikki stay for a night, so she says this for the "project about the moon". The next morning, the girls are happy because they managed to avoid the moon. Upset that Charlotte was mad at him the last day, Lewis tries to break up with her; Charlotte misinterprets his words, believing he's saying he wants to tell her the truth from now on, and shows him she is now a mermaid, to which he reacts badly.
48	"Bubble, Bubble, Toil and Trouble"	22 February 2008 (2008-02-22)	222
The girls realize Charlotte is a mermaid. Against Rikki's better judgement, they decide to try to help her transition into her new, changed form. Charlotte discovers her first power at the JuiceNet cafe, when a glass of juice evades her hand. Cleo is not pleased that she shares her power with Charlotte. Later, all four mermaids are forced to join a beach volleyball team to keep from failing. Charlotte accidentally touches water; when she escapes and frustratingly puts her hands on her tail, she evaporates the water and discovers her second power. After a victorious win because of Cleo's wind, the girls go to the JuiceNet cafe. Charlotte enthusiastically demonstrates her heating power to Rikki (who's not pleased either), and after experimenting realizes she has Emma's power as well. While the girls aren't thrilled, Charlotte is happy and believes she is a "super mermaid".
49	"Reckless"	29 February 2008 (2008-02-29)	223
Charlotte's enthusiasm over her newly acquired powers make the girls worried. They try to help her control them, but Charlotte misinterprets their actions as fear and trying to cut her off from her full potential. She accidentally reveals her fear of dolphins. When she gets stuck in a marine park with Ronnie the dolphin, out of sheer terror she nearly boils him to death. Cleo's attempts at satiating her and telling her to control herself only further irritates her. Charlotte thinks she's the only true mermaid. Later on, Nate tries to take Lewis's boat after Lewis refuses to pay Nate the fee for wrecking his jet ski. Charlotte furiously leaps into the water and nearly injures Nate in her attempts at revenge. The girls realize Charlotte is more uncontrollable than they first realized and it takes all of their powers to stop her.
50	"Three's Company"	7 March 2008 (2008-03-07)	224
Charlotte has "mastered" her powers and tells Lewis she's better than the girls and is therefore a "super mermaid". With Lewis's birthday coming, Charlotte is determined to plan the "perfect" party for him and refuses to accept the girls' ideas. Rikki gets fed up and leaves to spend time with Zane, excluding herself from the group. Charlotte invites all her friends rather than Lewis's and chooses Lewis's least favorite music. To keep Cleo and Emma from "ruining" the party, Charlotte secretly traps them inside the pool room, uses wind to shut the door, freezes the knob, and turns them into mermaids. To keep Lewis from getting suspicious, Charlotte lies to Lewis and tells him that the girls had to go. When Ash tells Rikki he can't find Cleo and Emma, Rikki rushes to the party, melts open the door, turns them back into girls, and arranges for a party boat - Lewis's favorite - to come so Lewis can escape. Lewis is thrilled to realize he can escape from Charlotte's total failure of a birthday celebration. As Lewis, Cleo, Emma, and Rikki board the boat, the girls tell Charlotte they know what she's done and that they no longer want to be her friend.
51	"Sea Change"	14 March 2008 (2008-03-14)	225
Charlotte's short-lived friendship with the girls is over. She demands loyalty from Lewis by saying he cannot talk or have anything to do with Rikki, Emma, or "especially Cleo". Lewis only reluctantly agrees, hoping it's just temporary. Meanwhile, Cleo is having difficulty evading washing the dishes, much to her father's displeasure. Upset at her father's pressuring and Lewis's avoidance of her, Cleo escapes and meets Charlotte. Using her unfair advantage - her additional powers and strength - Charlotte beats Cleo in a brief showdown, steals her locket, and tells Cleo that Lewis no longer wants anything to do with her. Rikki and Emma tell Cleo to stay away from Charlotte and Lewis, and no longer listen to her, refusing to help. Feeling crushed, heart-broken and helpless, she tries to call Lewis, but Charlotte has stolen his phone. Heart-broken, isolated and overpowered, Cleo tries to escape her human life, she runs away from home, only to find herself in a shark breeding ground. Lewis finds out that Charlotte stole his phone and is trying to isolate him. Angrily, Lewis breaks up with her, saves Cleo, and gets back together with her. Unfortunately, by choosing Cleo over Charlotte, Lewis has created an enemy more powerful than they could imagine. In the end, heart-broken Charlotte seeks revenge on Cleo.
52	"Unfathomable"	21 March 2008 (2008-03-21)	226
The final full moon of the season approaches. It will be Charlotte's first one, and to protect their secret, the girls try to warn her. Charlotte angrily retorts that she's "more mermaid than the three of [them] put together" and thrusts them into the air before dropping them and giving them bruises just as Ash appeared. Charlotte is convinced that Lewis made a mistake in choosing Cleo over her and is determined to remove the girls' powers. That night, while the girls are sealed inside Emma's house, Ash comes over. Tired of the mysteries, Ash demands an explanation from Emma. Charlotte purposefully looks at the full moon to make her full of strength and revenge, and begins causing mayhem in Emma's house by using her powers. The girls cannot fight back because Ash is in the house. As Charlotte planned, Lewis asks her to go to Mako Island; Cleo finds out and chases after them. Emma and Rikki then follow her to help her. When the three of them are together at Mako Island, Charlotte reveals that this full moon can permanently remove a mermaid's powers and that it is how her own grandmother, Gracie, became an ordinary girl again. The girls fight; while Charlotte is stronger than each of them individually, the girls work as a team, strike down her creations, and make her plan backfire. Charlotte is no longer a mermaid. Lewis is able to retrieve the locket the next morning and return it to its rightful owner, Cleo. Rikki asks Lewis that Charlotte will reveal the girls' secret and Lewis explains that she won't. Ash finally discovers Emma is a mermaid and reacts well to the news. This series ends with Ash, Zane, and Lewis watching the girls run into the ocean and swim off as mermaids.

Series three: 2009-2010

The third series began broadcasting on 26 October 2009 in the United Kingdom. This series centers around Cleo and Rikki coming to terms with the loss of Emma, who has left town and is traveling the world with her family. New characters are introduced, including Bella Hartley (Indiana Evans), a singer and mermaid since the age of nine with the power to turn water into gelatin, and Will (Luke Mitchell), a skilled diver who is trying to figure out the secrets of Mako Island, and who accidentally unleashes a powerful force which turns water against the mermaids. The girls must also deal with Zane, who attempts to exploit the secret of the girls and Mako Island after Rikki breaks up with him.

Episode	Title	Director	Writer	Original airdate	Production code
53	"The Awakening"	Jeffrey Walker	Joss King	26 October 2009 (2009-10-26) (UK)	301
With Emma away touring the world with her parents, Cleo and Rikki are forced to deal with their mermaid troubles alone when new arrival, Will, unleashes a powerful force at Mako which makes water turn against them. Bella reveals she is a mermaid to Cleo and Rikki, who accept Bella into their group.
54	"Jungle Hunt"	Jeffrey Walker	Anthony Morris	27 October 2009 (2009-10-27) (UK)	302
It's the first day back at school, Rikki is determined to stop Will from finding anything on Mako Bella tries to get close to Will. Lewis and Cleo try and figure out what happened to the moon pool by sending Bella out to distract Will from finding anything else about Mako Island. Rikki feels uneasy about leaving Will and Bella alone so she follows them in secret, luckily for Bella, Rikki catches up not a second too soon. Unfortunatly, Bella leads Will exactly where she dosen't want him; the Moon Pool.
55	"Keep Your Enemies Close"	Jeffrey Walker	Sam Carroll	28 October 2009 (2009-10-28) (UK)	303
Cleo becomes an assistant dolphin trainer. Will, who isn't allowed in the Dolphin trainning pool jumps in and helps the dolphin Cleo is training learn a trick he never did before. Cleo's boss was watching and she has to make the dolphin perform the trick again in front of a live audience. Rikki fires Nate's band after hearing his new song, leading to tensions with Bella, the lead singer.
56	"Valentine's Day"	Jeffrey Walker	Simon Butters	29 October 2009 (2009-10-29) (UK)	304
When Valentine's Day arrives, the girls worry about what their boyfriends will do for them. Bella tries to get close to Will, who doesn't seem to notice her. Cleo's father meets Samantha, a woman who is in charge of his boat's license, but Kim accidentally pushes her into the water.
57	"Big Ideas"	Jeffrey Walker	Philip Dalkin	30 October 2009 (2009-10-30) (UK)	305
Zane is having money troubles with the café, and Rikki discovers they are going bankrupt. Meanwhile, Lewis and Cleo continue to study the leaking rock wall at Mako.
58	"Secrets & Lies"	Jeffrey Walker	Simon Butters	2 November 2009 (2009-11-02) (UK)	306
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.
59	"Happy Families"	Jeffrey Walker	Max Dann	3 November 2009 (2009-11-03) (UK)	307
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.
60	"Kidnapped"	Jeffrey Walker	Chris Roache	4 November 2009 (2009-11-04) (UK)	308
During a full moon, the girls stay at Cleo's and Bella is attacked by the water creature. At the same time, Will decides to return to the moon pool after making the connection between his previous encounter with the moon pool waterfall and the timing of the full moon.
61	"The Sorcerer's Apprentice"	Jeffrey Walker	Philip Dalkin	5 November 2009 (2009-11-05) (UK)	309
Cleo starts to experiment on the moon pool water without Lewis' knowledge, but things start going wrong when Cleo's fish Hector gets trapped in the bubble of floating water. Meanwhile, Lewis has to play golf with Cleo's father.
62	"Revealed"	Jeffrey Walker	Sam Carroll	6 November 2009 (2009-11-06) (UK)	310
After Bella gives Will a shell-like fossil she found while swimming, Will becomes suspicious as the fossil is of a rare kind. Rikki realizes how close Will is to finding out their mermaid secret and warns Bella to stay away from Will. At the end, Will finds out Bella is a mermaid.
63	"Just A Girl At Heart"	Jeffrey Walker	Anthony Morris	TBA	311
Bella struggles with the thought that Will is only spending time with her because he is interested in her as a mermaid rather than her as a girl.
64	"Crime & Punishment"	Jeffrey Walker	Max Dann	TBA	312
After all the money Rikki makes with the café she gets captured. Cleo and Bella are forced to tell the trio's secret to Will in order to save Rikki.
65	"To Have & To Hold Back"	Jeffrey Walker	Simon Butters	TBA	313
Cleo realizes it is time to let Lewis move on in his life as he goes to America to study science. (This is Angus' last episode.)
66	"Mermaid Magic"	Colin Budds	Anthony Morris	TBA	314
67	"Power Play"	Colin Budds	Anthony Morris	TBA	315
68	"The Dark Side"	Colin Budds	Sam Carroll	TBA	316
69	"A Magnetic Attraction"	Colin Budds	Sam Carroll	TBA	317
70	"Into The Light"	Colin Budds	Sam Carroll	TBA	318
71	"Breakaway"	Colin Budds	Anthony Morris	TBA	319
72	"Queen For A Day"	Colin Budds	Samantha Strauss	TBA	320
73	"The Jewel Thief"	Colin Budds	Simon Butters	TBA	321
74	"Mako Masters"	Colin Budds	Philip Dalkin	TBA	322
Cleo, Rikki, and Bella think they have finally mastered their old and new powers along with conquering the powers the water tentacle has over them.
75	"Beach Party"	Colin Budds	Anthony Morris	TBA	323
Cleo, Rikki, and Bella debate going to a beach party they've been invited to due to how close it will be to water but decide to attend, much like episode 2 from season one. But it doesn't take long before rikki has a cooler of water dumped on her by some trouble makers.
76	"Too Close For Comfort"	Colin Budds	Max Dann	TBA	324
The girl's secret is nearly discovered by Cleo's father when the three girls fall off his boat when Mr. Sertori makes a quick turn.
77	"A Date With Destiny"	Colin Budds	Chris Roache	TBA	325
After another attack by the water tentacle the girl's finally realize what it's been after, what they will have to do to stop it, and why they became mermaid's in the first place.
78	"Graduation"	Colin Budds	Joss Kingac	TBA	326
Bella, Rikki and Cleo must stop a freak comet that is heading for Mako island. After stopping the comet, the water tentacle tries to attack one last time, the girl's realize the only way to stop it for good is to give up their powers, and being mermaids. The girls also graduate with a surprise.

Television episode compilation films

Title	Original airdate
"H2O: Just Add Water: The Movie"	8 June 2007 (2007-06-08)
This TV movie summarised the events of the beginning of series one, using clips from the episodes "Metamorphosis", "Pool Party", "Catch of the Day", "Party Girls", "Lovesick", "The Denman Affair" and "The Siren Effect".
"H2O: Metamorphosis"	14 March 2008 (2008-03-14)
In the United States, "Metamorphosis" and "Pool Party" premiered as a one hour movie.
"H2O: Exposed"	20 June 2008 (2008-06-20)
In the United States, "Dr. Danger" and "A Twist in the Tail" premiered as a one hour movie called "Exposed".
"H2O: Just Add Water: And Then There Were Four"	7 September 2008 (2008-09-07)
In some countries such as Romania, Bulgaria and Russia, the episodes "The Gracie Code (Part 1)", "The Gracie Code (Part 2)" and "And Then There Were Four" are combined into a 60 minute television movie. This version aired only in central and eastern Europe on Jetix.

External links

• Episode guide at the Internet Movie Database
• Episode guide at TV.com