Series / H₂O: Just Add Water

No ordinary girl.

I've got a special power
That I'm not afraid to use
So come on this is my adventure
This is my fantasy
It's all about living in the ocean being wild and free!
'Cause I'm no ordinary girl
I'm from the deep blue underworld
Land or sea
I've got the power if I just believe
'Cause I'm no ordinary girl
I'm from the deep blue underworld
Land or sea
The world's my oyster, I'm the pearl
No ordinary girl...

— The Theme Tune

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 TeenNick as simply H₂O. The story focuses on three friends who transform into mermaids whenever they touch water following "The Splash Method" (when they are wet they turn into mermaids, and when they are dry they transform back). In the first episode, the girls are trapped in a volcanic cave on the mysterious Mako Island, where they swim in a magical pool during a full moon in an attempt to swim out. The next day, they find that they transform ten seconds after getting their skin wet. The trio decide to enlist Cleo's scientist best friend Lewis to help them understand their new predicament as they conceal their tails and newfound water powers from their friends and families.

Created by Jonathan M. Shiff, it’s mostly about the girls' 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 and a new girl, Bella, added to replace Emma. A spinoff series, Mako Mermaids: An H₂O Adventure, is available on Netflix. A short-lived Animated Adaptation, H₂O: Mermaid Adventures, is also available on Netflix and Prime Video.

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This series provides examples of:

• Actually, That's My Assistant: Zane initially assumes that Greg is Dr. Denman, rather than her assistant.
• Adults Are Useless: And clueless and easily distracted, and readily accept some really bizarre excuses with no question. Particularly noteworthy is Cleo's father, who fails to notice how little Cleo likes Charlotte when he hires the latter as a tutor for Cleo, and does nothing to rein in Kim's brattiness.
  • Averted with characters like Miss Chatham and Max, who have experienced the mermaid problems and offer helpful advice to the girls.
• All Abusers Are Male: Averted with Charlotte, who starts her relationship with Lewis by stalking him and pushing him to ask her out even when he's not that interested; later on, she takes control of his phone, bosses him around, and begins to prevent him from seeing his other friends.
  • Sophie in Season 3 is a similar controlling case.
• All Your Powers Combined: The powers will be divided by those in the moon pool when it's active during the full moon. When Charlotte becomes a mermaid, she gains all three of the powers because she is the only one in the pool. Bella in the third season also has three powers, as 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).
• Anti-Climax: The Series Finale raises the stakes significantly, with a comet that threatens to wipe out all life on Earth. How do the girls defeat it? By using their powers to create an artificial water tentacle in the moon pool, and somehow deflect the comet's path with it. Compared to the finales of the two prior seasons, it's something of a let-down, and a lot of plot threads are ultimately never resolved. This likely has to do with it being a Post-Script Season.
• Armor-Piercing Question: episode 1.09
  Emma: We've made a fool of him. You've gotten even. Anything else you do is just you wanting to hurt someone. Is that who you are?
• As You Know: Two minutes into the season 2 premiere Kim reminds her sister that their parents have now split up, for the audience's benefit.
  • This trope turns a conversation between Cleo, Emma, and Rikki into an info dump for Charlotte, who's eavesdropping.
• Arc Villain:
  • Season 1: Dr. Denman
  • Season 2: Charlotte
  • Season 3: Sophie
• 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: Lewis.
• Bait the Dog:
  • Charlotte spends most of series 2 trying to be nice to people except for Cleo, it's the main characters that are doing nasty things to her. This changes in the last four episodes.
  • Zane is a sympathetic character for the first two and a half seasons despite his bad boy image, helping the mermaids escape the first season's Big Bad and dedicated to upholding The Masquerade like everyone else. Midway through Season 3, though, after he kisses another girl and then lies about it to Rikki, he threatens to expose her secret to the world in a last-ditch attempt to make her stay with him. He does see the error of his ways by the end, but Rikki's completely justified in never wanting to associate with him again after that!
• Bathtub Mermaid: Inverted. The mermaid characters are humans by default, and a special mermaid tail had to be made for all of Cleo's scenes that took place in the bathtub because she'd turn into a mermaid upon contact with any water.
• 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.
• Be Careful What You Wish For: Small one, but in the episode in which Cleo can grant wishes, Kim wishes she can "just take a shower whenever she wants". A second later, the lawn sprinkler turns on, completely soaking her
• Birthday Episode:
  • There was one for Cleo. The one her dad organised for her was embarrassingly childish while the one her friends organized was much more to her liking.
  • Later, there was one for Lewis.
  • There was one for Emma's dad in an episode.
  • Although not entirely focused on the birthday itself, there is one for Rikki in season 3. This is when her life begins to fall apart.
• Blessed with Suck: For our heroines, contact with water is not always a pleasant thing.
• Body Horror: In Season 2's "Fish Fever", Emma is poisoned after cutting her finger on a piece of coral and starts mutating into a white scaled monster.
• Bottle Episode: "The Siren Effect" which takes place almost entirely in Cleo's house, save for two scenes in the Juice Café and one brief shot of Byron on the beach. Also the only episode not to feature a mermaid transformation at all.
  • Also "Under The Weather" which happens entirely in Emma's house apart from a brief ending scene in Cleo's room. No costly special effects are used and the one mermaid transformation scene is very brief.
• Bound and Gagged: Rikki ends up bound and gagged by counterfeit smugglers in the third season episode Crime and Punishment.
  • Also happens to Zane in Season 1's "A Twist in the Tale".
• Boyfriend-Blocking Dad: Cleo's, who seems to be afraid that his daughter will get pregnant with triplets if a boy so much as holds her hand. He slowly warms up to Lewis however, preferring that Cleo be with him than someone like Nate. Averted with Emma's father, who is nice and normal, and Rikki's is only hostile to Zane because of a misunderstanding.
• Bragging Theme Tune:
  I've got a special power/that I'm not afraid to use...
  Cause I'm no ordinary girl/I'm from the deep blue underworld...
• 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.
• Cast Calculus: Personality gets divided up between the three main characters, Emma being cool and organized, Rikki fiery and temperamental, and Cleo somewhere in between, being the more passive who acts as peacemaker when Rikki and Emma fight.
  • They are even color-coded in Season 1- Emma wears blue, Rikki wears Red, and Cleo wears purple.
  • In Season 3, with Emma gone and replaced with Bella, and Lewis later Put on a Bus, the cast relationships are shuffled around a lot, while still seeming like natural Character Development, fortunately.
• Childhood Friends:
  • Emma and Cleo are childhood friends.
  • Emma and Zane are family friends, and have known each other since they were 3. They don't much like each other these days, but Emma's mom makes it sound like they might've been friends when they were small.
• Chuck Cunningham Syndrome: 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.
• Clingy Jealous Girl: Season 2 character Charlotte, who admittedly takes turns with Cleo at this. Sophie from Season 3 is rather clingy towards her own brother.
• 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.
• Coconut Super Powers: We rarely see Emma actually freezing anything. We see her pointing her hands at an object, a CGI shot of molecules freezing and then it cuts to the object already frozen. While there is an effect to show the girls turning into mermaids, they more often show the girls falling to the floor and being in mermaid form in the next shot, or else diving into the water already transformed.
• Color-Coded Characters: 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.
• Diegetic Soundtrack Usage: In the Season 3 finale, Bella performs the theme song at Rikki's Cafe.
• "Do It Yourself" Theme Tune: Even though the 3rd season reused the OP from the 1st two seasons, this version is sung by Bella's actress, Indiana Evans.
• Does This Remind You of Anything?: The girls waking up after the Full Moon is quite similar to any teen/college student waking up after a particularly boozy night out not having a clue what they might have done.
  • One to do with the moon,which happens once a month and gives the girls bizarre mood swings.
• Early-Installment Weirdness: In the first few episodes, Zane displays unprovoked and open hostility on several occasions especially towards Cleo. It gets toned down over the course of the first season.
• Evil Redhead: Charlotte, sort of. And Sophie in Season 3.
• Evolving Music: Played with. The show used the same theme song throughout its entire run, but it was performed by a different artist each season, the lyrics and even tempo remaining precisely the same.
• Failure Is the Only Option: In the first two seasons, at least one girl gets possessed by the full moon every time no matter how many precautions they take. They eventually discover that the moon pool water is the only safe place (which doesn't explain their nonchalance at seeing the moon before they get there) and the whole thing is dropped by Season 3.
• Fake Faint: Cleo pretends to faint in "Under the Weather" to avoid the girls having to go out in the rain (as that would turn them into mermaids). Unfortunately, this starts a chain of events escalating until they end up in quarantine with the medical specialists believing they're dealing with a serious unknown illness.
• Fanservice: 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.
  • Fanservice Pack: All three girls, as well as Lewis in season 2. All the actors were a bit older, so it was okay to have them used for Fanservice.
• 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.
• Forgotten Phlebotinum: Everyone just forgets about the wish-granting potion after its initial episode. Justified as it would be a blatant Deus ex Machina otherwise.
• Freudian Trio: Rikki is the id, Cleo is the ego, and Emma is the superego.
• Getting Sick Deliberately: In "Under the Weather", a rainstorm traps the girls at Emma's house, which fears them as touching water will trigger their mermaid transformations; to avoid revealing their secret, they use their mermaid powers to magically make themselves deliberately ill.
• The Glorious War of Sisterly Rivalry: Cleo and Kim's bickering occasionally manifests as this, naturally.
• Heel–Face Turn: Charlotte at the very end of Season 2, after having already done the inverse. Sophie in Season 3.
• 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.
• 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.
• Ice Magic Is Water: Emma's powers are ice-themed as extensions of her water control.
• Idiot Ball: So much of the drama could be resolved if the characters would actually try to properly communicate with each other instead of just being snide and evasive with each other.
• 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.
• Insists on Paying: Zane buys gifts, like an engraved iPod for Rikki, who resists.
• Irony: Becoming a mermaid ended Emma's career as the champion of the school swim team.
• Jerk with a Heart of Gold: Rikki is snarky and blunt even on the best of days, but she'll always help out a friend in need, doesn't want to hurt people with her words and apologizes when that happens, and actively fights criminality on a few occasions.
• Karma Houdini: Let's recount Dr. Denman's crimes. Four counts of kidnapping, with the intent of forcibly experimenting on three people, and threatening Lewis' life to keep the girls in line. No legal trouble, no harm done to her career, nothing. No one other than a few people ever find out, so not even her reputation suffers. She just...doesn't get to do the experiments she wanted.
• 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. Doubly so for Cleo's case, as she enchanted Lewis with her siren song, putting them both under the influence when they kissed.
• Last Day of Normalcy: The first episode, "Metamorphosis", introduces the three heroines (Emma, Cleo, and Rikki), shows them going through a life as Ordinary High School Students, and has them shipwrecked to Mako Island where they first discover the moon pool, and coming into contact with it once a full moon passes over grants them the ability to turn into mermaids whenever they touch water.
• Letting Her Hair Down: The mermaid transformation does this to the girls for no apparent reason. Also Rikki is rarely shown with her hair down at first but wears it down more often as she undergoes Character Development.
• Love Potion: In one episode, Nate gets hold of some ambergris, which makes him irresistible to the mermaids.
• Love Triangle: Between Cleo, Lewis and Charlotte in Season 2.
• Lunacy: Multiple:
  • Moonlight, when seen through the Moon Pool, turns people into mermaids and grants them powers.
  • The effects of a full moon cause the girls' powers to lose control.
  • In the final episode, the full moon is overhead at 7:32. The full moon should only be overhead within an hour or so of midnight.
• MacGuffin Location: Mako Island often seems to serve this purpose. Turns out there are other places like it, as this is where Bella got her powers.
• Magical Girls
• Magic Pants: During the shift from human to mermaid form not only do clothes disappear until the girls become human again but any hair decorations and hairspray also disappear, leaving the transformee's hair untied. This seems to work both ways, as when Emma dyed her hair red in mermaid form, it reverts to her natural blonde color when she is human.
• Making a Splash: Seldom used offensively, though, except as a prank.
• Manipulative Bastard: Charlotte counts as a minor version of this. It escalates near the end of Season 2.
• Mermanity Ensues: The series is based around its three leads being turned into mermaids as a result of falling into a pool during the full moon, causing them to transform 10 seconds after they get wet. They try to figure out what to do now that they have these powers, and trying to hide this fact from the public eye.
• Muggle–Mage Romance: The mermaids have had relationships with ordinary men. Cleo and Lewis is the longest-running one, though not without a few hiccups.
• 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 café and eventually starts spreading into the café 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.
• Offscreen Reality Warp: On several occasions, the girls get out of the water offscreen and immediately take on some bad guys dry and in human form. It has been established (and it is a frequent plot point) that drying and transforming back takes quite some time.
  • They also meet up on Mako Island for some casual talk regularly without lying in the sand for hours beforehand.
• Organic Bra: In mermaid form, the girls have scales in exactly the same pattern as a bra, complete with straps.
• Our Mermaids Are Different: Like in films like Splash, a dry mermaid has human legs and a wet mermaid has fins. Mermaids also hold Elemental Powers and magic.
• Parental Bonus: Emma's behaviour at her first Full Moon is going to make most parents chuckle with how similar it is to a teenager getting drunk for the first time at a family gathering.
• Playing Sick: The girls had to do this in "Under the Weather" because it was raining outside, however things got a bit out of hand...
• Plenty of Blondes: Blondes seem to make up more than half the cast. Rikki, Emma, Lewis, Byron, Miriam, Bella, Will...
• Powers in the First Episode: The first episode "Metamorphosis" has Rikki, Emma and Cleo discover Mako Island and the Moon Pool, which bestows them their mermaid powers and they transform for the first time.
• 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: Multiple cases.
  • Between the first and second season, Cleo and Kim's mother leaves and divorces their father, never to be seen again.
  • In Season 3, Emma and her family has left town to travel around the world. Later that season Lewis leaves to go study in America.
• Real-Place Background: Sponsored by Australia's Gold Coast tourist board and Sea World.
• 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?
• Right Behind Me: When Emma is complaining about Ash to the other workers at the cafe.
• Running Gag: When the mermaid trio get wet by accident and transform while in a standing position, this is immediately followed by falling to the ground as their tails can't hold them in a standing position.
• Scenery Porn: Many Americans hadn't really heard of the Gold Coast before this, but it's very pretty.
• Screw the Rules, I Have Supernatural Powers!: Charlotte enters the moon pool alone. She develops all three of the girls' powers, and turns out to be the most talented at learning them. To put it mildly, this goes to her head to the point of nearly killing Nate, then Cleo's favorite dolphin, Ronnie, and finally directly attacking the girls.
• Seashell Bra: While not exactly seashells, when in mermaid form the girls magically develop bras that match their tails. Like the tails, they have golden scales, and disappear when they transform back into humans.
• Secret Identity: The girls have to keep their mermaid lives a secret to most others, especially their families.
• Ship Sinking: Rikki/Zane is pretty thoroughly torpedoed in Season 3, as the relationship becomes a deconstruction of All Girls Want Bad Boys. It also looks like this would happen to Cleo/Lewis for a while once he's Put on a Bus, but is averted as he's Back for the Finale.
• Shout-Out:
  • To various things, one being that Rikki does Spider-Man's signature hand gesture when she tries to figure out her water power.
  • The episode "Red Herring" is an obvious reference to a certain red haired mermaid.
  • One of the episodes is called "Bad Moon Rising".
• Slap-Slap-Kiss: Rikki and her on-and-off again boyfriend.
• Stealth Hi/Bye: Miss Chatham does this to Cleo in her first several appearances while delivering cryptic warnings.
• Super-Power Meltdown: Happens every time there's a full moon to the three girls. Which is often, and quite painful and scary for them.
• Tempting Fate: All three episodes of the second season that features the girls being affected by the full moon has an early scene in which at least one of the girls tells Lewis that they can handle the full moon without his help. All three times, all three girls end up under the moon's influence anyway.
• They Would Cut You Up: Part of the girls' justification for hiding their status as mermaids.
• Title Drop: Dr. Denman does this the most, surprisingly. At least, only the ‘Just Add Water’ part. One in ‘The Denman Affair’ as part of her research paper title, and another in ‘A Twist In The Tail’ as she is experimenting with a fin scale found near the Moon Pool.
• Total Eclipse of the Plot:
  • The Season 1 finale "A Twist in the Tail" gives us a once-a-month eclipse that can take away a mermaid's powers for twelve hours if they are in the Moon Pool by then.
  • The Season 2 finale "Unfathomable" gives us a really strong eclipse happening every fifty years; anyone who is in the Moon Pool during this will lose their powers forever.
• Tranquil Fury: Rikki lapsed into this when she found out that she was tricked into working for an illegal fish selling operation.
• Transformation Fiction: A major focus of the story is how the Involuntary Shapeshifter status of the girls and aim to keep their mermaid status a secret affects their lives.
• Transformation Sequence: The girls' mermaid transformation is initiated ten seconds after touching water, in which they flash blue for a moment before changing.
• "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.
• Water-Triggered Change: The mermaid girls change forms when in contact with water. Even if the girls get just a little wet, like if they're taking a bath or washing their hands, it'll trigger the transformation, which leads to a lot of awkward situations.
• What Did I Do Last Night?: The girls usually find themselves wondering this having been affected by the full moon.
• When the Planets Align: Any mermaid who is in the Moon Pool during a planetary alignment will have their powers increased; anyone in it during a 50-year planetary alignment will lose their mermaid powers forever.
• 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.

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We've got to stick together
Because the best things come in three
Want it to last forever
All the magic and fun at sea
So come on this is our adventure
There's no telling where we'll go
But all I want is just to live amongst the H₂O