H₂O: Just Add Water

H2O: Just Add Water is an Australian live-action series for preteen-to-teenage girls that has been shown in North America on Nickelodeon and currently shows on Teen Nick as H2O. The story focuses on three friends who gain magical powers over water and after a trip to the mysterious Mako Island, turn into mermaids following "The Splash Method" (when they are wet they turn into mermaids, and when they are dry they aren't) after swimming in a magical pool during a full moon.

The three girls are:

 * Emma Gilbert (Claire Holt), the "leader" of the group, who is a rather serious an responsible girl. She is a bit of a Control Freak and has powers to freeze water and manipulate ice, snow, and clouds. Her actress is noticeably missing from the third series; she left to film a straight-to-video prequel to The Messengers.
 * Cleo Sertori (Phoebe Tonkin) is the brunette of the group and a bit awkward but eventually becomes more outgoing. Her powers are manipulating the shape of water and she later gains the Razor Wind power too.
 * Rikki Chadwick (Cariba Heine) is the "Wild Child" of the group, who in appearance and attitude is similar to Sam from I Carly (although Rikki notably pre-dated her). She is the new girl in town but not a Naive Newcomer, because she is rebellious and confident. Her powers initially involve manipulating heat in water (i.e. boiling it), but eventually extend to control over fire and lightning.

The series mostly is about the girl's powers and dealing with them in real life. There were initially going to be only two seasons, but due to popular demand a third season was added, with several of the characters missing.

Tropes related to the series

 * Adults Are Useless: And clueless and easily distracted, and readily accept some really bizarre excuses with no question.
 * Averted with characters like Miss Chatham and Max who have experienced the mermaid problems and offer helpful advice to the girls.
 * All Your Powers Combined: Apparently the powers will be divided by those in the moon pool when it's active during the full moon. When Charlotte became a mermaid, she gained all three of the powers because she was the only one in the pool.
 * That doesn't really explain Bella, however, who only has one power even though she was alone in her moon pool.
 * Alpha Bitch: Miriam is not a nice person.
 * Annoying Younger Sibling: Cleo's younger sister Kim is a rather extreme case. Elliott, Emma's brother, is an aversion as he is usually nice, friendly and 'squeaky clean' (Rikki's words).
 * Aw Look They Really Do Love Each Other: A sisterly version between Cleo and Kim occasionally shows up throughout the series.
 * The Beautiful Elite: This show is a pretty bad offender of this.
 * Lampshaded in Season 3 when Rikki tells new girl Bella that she only likes Will because "he's the only guy in a five-mile radius not to swoon over her".
 * Back for The Finale:
 * Bait the Dog: Charlotte spends most of series 2 trying to be nice to people, it's the main characters that are doing nasty things to her. This changes in the last four episodes.
 * Beauty Brains and Brawn: With Cleo as Beauty, although she started off as somewhat Hollywood Homely.
 * When Emma leaves in season 3, Cleo eventually went into Brains territory while Bella took over the Beauty spot.
 * Black Best Friend: Tiffany, Miriam's friend in Season 1.
 * Blonde Brunette Redhead: Well, blonde, brunette and strawberry blonde. But which one of the blondes is the smart one?
 * In "Red Herring", Emma dyes her hair bright red (a Shout Out to The Little Mermaid).
 * When Charlotte becomes a mermaid (but then it would be Blonde Blonde Brunette Redhead or Blonde Brunette Redhead (strawberry blond) Redhead
 * Body Horror: When Emma in a Season 2 episode is poisoned after cutting her finger on a piece of coral, she starts mutating into a white scaled monster.
 * Bratty Half Pint: Kim, Cleo's sister.
 * Brother Chuck: Some of the Season 1 characters are no where to be found in Season 2, such as Miriam and Byron. Also Ash in Season 3.
 * Brought Down to Normal: In the Season 1 finale the girls lose their powers for twelve hours after entering the moon pool during an eclipse. And in the Season 2 finale Charlotte tries to get the girls into the moon pool during the fifty year moon in order to make them permanently lose their powers, thinking that she would be the only special girl for Lewis if she did. The other girls manage to overpower her and drop her into the moon pool, causing her to lose her powers forever.
 * Calling the Old Man Out: Zane does this to his father, after helping the mermaids escape from Dr. Denman in the Season 1 finale.
 * Cloudcuckoolander: Louise Chatham appears to be one of these.
 * Looking at a full moon (or even at just a reflection of one) has the effect of turning the mermaids into this. It wears off at sunrise the next morning, but until then, you can expect some crazy things to happen.
 * Clingy Jealous Girl: Season 2 character Charlotte. Sophie from Season 3 is rather clingy towards her own brother.
 * Color Coded for Your Convenience: Not obvious at first but in Season 1 the girls are often coded by the color of their clothing: Rikki (the brawny one, heating power) wears red, Emma (the restrained one, ice power) light blue and Cleo (who gets often caught in the middle) wears purple/pink.
 * Control Freak: Emma, and later Charlotte.
 * Dawson Casting: averted in the first two seasons as the three leading actresses were still in high school, but the gap between Seasons 2 and 3 left them playing high school seniors while they were 20/21 in the final season.
 * Did Not Do the Research: The Lunar Eclipse in one episode was far too speedy. Same issue:
 * Do It Yourself Theme Tune: Even though the 3rd season reused the OP from the 1st two seasons, this version is sang by Bella's actress, Indiana Evans.
 * Evil Redhead: Charlotte, sort of. And Sophie in Season 3.
 * Fan Service: Season 1 not so much since they were all about 15 but being able to turn into mermaids doesn't stop the girls from walking around in bikinis a lot of the time. And the character of Will who spent the majority of his first episode of the series shirtless.
 * Fan Service Pack: All three girls, as well as Louis in season 2. All the actors were much older so it was okay to have them used for Fan Service.
 * Floating Water: Cleo's power lets her do this.
 * In Season 3, the water from the wall of the cave the moon pool is in combined with the water in the moon pool creates an anti-gravity ball of water.
 * Getting Crap Past the Radar: See Kick the Dog below for the specifics but one episode has Cleo left depressed and she swims out into the middle of a known shark breeding ground. Yep, probably the first kids' programme to show a character nearly committing suicide.
 * Guilty Pleasure
 * Heel Face Turn: Charlotte in Season 2. Sophie in Season 3.
 * Hollywood Nerd: Cleo's boyfriend Lewis.
 * Hollywood Tone Deaf: Cleo, as demonstrated in "The Siren Effect". The same episode has Rikki doing some truly awful karaoke as well though she's clearly doing it badly on purpose.
 * Hot Scientist: Dr. Denman. The characters even mention she looks more like a Baywatch actress than a scientist.
 * In season 3, Cleo becomes one of these.
 * How Do I Shot Web: Each girl spends an episode wondering what her power is. When Rikki tries to find her power the first gesture she makes is the one Spider Man uses to shoot web.
 * An Ice Person: Emma's powers, reflecting her character.
 * This strangely parallels Sailor Mercury's powers changing with the introduction of Sailor Neptune in Sailor Moon, although with all the Shout Outs in the show this is perhaps not quite an accident.
 * I Just Want to Be Normal: Gracie, one of the three original mermaids felt this way. Louise Chatham also mentions that she also eventually found the burden of being a mermaid too much and gave it up. Mostly averted with the main trio, although Emma and Cleo at first had some trouble adjusting to their new situation, since Emma had to quit the swim team and Cleo hadn't yet learned how to swim and was somewhat afraid of water.
 * I Just Want to Be Special: When Charlotte learns that her grandmother Gracie was a mermaid, and later discovers that Cleo, Emma and Rikki are mermaids as well, she decides that she wants to become a mermaid herself. She succeeds.
 * Idiosyncratic Wipes: Splashes of water.
 * Image Song: Bella is fond of these (and the only one of he mermaids to do so), due to singing songs in Season 3.
 * Irony: Becoming a mermaid ended Emma's career as the champion of the school swim team.
 * Jerk With a Heart of Gold: Rikki.
 * Karma Houdini: The girls themselves in "Under The Weather" where it's raining outside so they fake being sick. They use their powers to fake some symptoms and they end up having the entire house quarantined in fear of a tropical disease. At the end Emma lies to say they faked being sick to get out of a biology exam. The girls don't get punished at all and the end of the episode even shows them about to go to a party. Most lenient parents ever.
 * Kick the Dog: Charlotte stealing Cleo's locket and making her believe that Lewis no longer cares about her.
 * Kissing Under the Influence: All three girls kissed their love interests in Season 1 while under the influence of the full moon.
 * Lonely Rich Kid: Zane.
 * Love Potion: In one episode, Nate get's hold of some ambergris which makes him irresistible to the mermaids.
 * Love Triangle: Sort of, between Cleo, Lewis and Charlotte in Season 2.
 * MacGuffin Location: Mako island often seems to serve this purpose.
 * Magical Girls
 * Making a Splash: Seldom used offensively, though, except as a prank.
 * Manipulative Bastard: Charlotte may count as a minor version of this.
 * Nice Job Breaking It Hero: In one episode, the mermaids and Lewis make a magic potion that can supposedly allow mermaids to grant wishes. However, when it apparently doesn't work, Rikki declares it a waste of time, and she uses her powers on it one more time before leaving. This causes the potion to start growing and it spreads all over the coolroom in the Juicenet cafè and eventually starts spreading into the cafè itself. Later in the episode, she also suggests to Emma that she try to use her power to freeze the stuff, which only causes the stuff to spread even faster.
 * No Export for You: In the US, the last half of Season 2 and the entire third season were held up substantially. The show ended half-way through Season 2 during re-airings in 2008. When Teen Nick began re-airing the series in 2011, the remaining episodes still weren't being aired - instead cycling through the same aired episodes again and again. Finally averted on January 16, 2012, where the final thirteen episodes of Season 2 were aired in a Teen Nick marathon leading into the US premiere of Season 3. (3 Years after the UK aired the 3rd season.)
 * The rest of the world, including its native Australia, didn't get the 3rd season until 2010, whereas the UK got it first in 2009.
 * Our Mermaids Are Different
 * Overprotective Dad
 * Playing Sick: The girls had to do this in one episode because it was raining outside, however things got a bit out of hand...
 * Power Trio
 * Puppy Love: in-universe. One episode had Emma's younger brother Elliot trying to ask Cleo's younger sister Kim out. Kim just took advantage of him and kept bossing him around. He eventually got tired of her attitude and ditched her at the end of the episode.
 * Put On a Bus: In Season 3, Emma and her family has left town to travel around the world. Later that season
 * Reed Richards Is Useless: The rare mermaid guide Lewis bought. The girls don't seem interested until Cleo thinks of a way to reunite her parents, and then it's lost while dealing with the wish-granting potion. There's no telling what other information was lost - even a way to only change in seawater, and stay human in freshwater?
 * Scenery Porn / Real Place Background: Sponsored by Australia's Gold Coast tourist board and Sea World. Many Americans hadn't really heard of the Gold Coast before this, but wow, is it pretty.
 * Screw the Rules I Have Supernatural Powers: Charlotte entered the moon pool alone. She developed all three of the girls' powers, and turned out to be the most talented at learning them. To put it mildly, this went to her head to the point of nearly killing Nate, and then Cleo's favorite dolphin, Ronnie.
 * Shout Out:
 * To various things, one being that Rikki does Spider Man's Memetic Hand Gesture when she tries to figure out her water power.
 * The episode "Red Herring" is an allusion to the episode "Rumors" from The Suite Life of Zack and Cody in which Cody Martin wants to change his look just like Emma and they both end up dyeing their hair red and they both see it and they both end up hating it.
 * One of the episodes is called "Bad Moon Rising".
 * Slap Slap Kiss: Rikki and her on-and-off again boyfriend.
 * Superpower Meltdown: Happens every time there's a full moon to the three girls. Which is often, and quite painful and scary for them.
 * Girls and the moon cycle...
 * The Merch: CDs and books have become available in Australia; Kate Alexa's made herself famous by the CD. In the US, dolls of the 3 mermaids were available for a short time.
 * Theme Tune Cameo: In "Sink or Swim", Emma refers to herself as "Not an ordinary girl."
 * In the Season 3 finale, Bella performs the theme song at Rikki's Cafe.
 * They Would Cut You Up: Part of the girls' justification for hiding their status as mermaids.
 * Three Amigos: More Beauty Brains and Brawn.
 * Tomboy: Rikki.
 * Too Dumb to Live: The girls have been warned of the effects of the full moon. Yet it - an inanimate hunk of rock - manages to outwit them every single night it's visible (at least for the first season and a half or so; after that, they just become... more immune to it, rather than mastering the art of not looking at it).
 * The first moon was unavoidable. #2 was a spot they missed (it ended up reflected as Cleo went to wash her hands after using the toilet).
 * The third time also had the moon light reflect of various objects until it was reflected in a glass of water that Rikki was holding. In the first episode of the second season, they didn't realize that the full moon was already out because Lewis had mistakenly come to the conclusion that the moon wouldn't rise for another hour because of a computer program he was using. They usually seem to come under the influence of the full moon due to having missed a spot, or some other unexpected event.
 * Tsundere: Rikki.
 * Tranquil Fury: Rikki lapsed into this when she found out that she was tricked into working for an illegal fish selling operation.
 * Walk On the Wild Side Episode: Emma gets this twice. The first is a small one where she decides to dye her hair red after being called predictable and the second has her completely slacking off and throwing a Wild Teen Party in her house. She's learnt her lesson by the end of the episode of course. Rikki of all people has to calm her down.
 * What Did I Do Last Night: The girls usually find themselves wondering this after having been affected by the full moon.
 * Who Wears Short Shorts: All the girls though justified since it's Australia.
 * Wild Teen Party: Emma throws one of these to show she can be fun and it naturally gets out of hand with her mother's crystal ornament getting broken. In another episode Rikki trashes the kitchen with her powers and Emma lies saying they had a party.
 * You're Just Jealous: This gets thrown around a couple of times in the episode where the mermaids are infatuated with Nate.