Metamorphosis (H2O: Just Add Water)

H2O: Just Add Water
Company type	Television series
Industry	Entertainment
Founded	July 7, 2006; 20 years ago
Headquarters	Australia
Area served	Worldwide (aired in more than 120 countries)

Adapted from the English Wikipedia article Metamorphosis (H2O: Just Add Water), available under CC BY-SA 4.0Updated 11 August 2025

The following compilation presents the episode guide for the Australian series H₂O: Just Add Water, which initially premiered on Network Ten in Australia and has since been aired in more than 120 countries worldwide. The first season debuted on 7 July 2006, followed by the second season on 28 September 2007. The third season was first broadcast in the UK on 26 October 2009, with its Australian release occurring on 22 May 2010.

Series overview

Season		Number of episodes	Original broadcast dates
Season		Number of episodes	Season start	Season end
	1	26	7 July 2006 (2006-07-07)	29 December 2006 (2006-12-29)
	2	26	28 September 2007 (2007-09-28)	21 March 2008 (2008-03-21)
	3	26	26 October 2009 (2009-10-26) (UK)	16 April 2010 (2010-04-16) (UK)

Series 1 (2006)

Emma Gilbert (portrayed by Claire Holt), Cleo Sertori (Phoebe Tonkin), and Rikki Chadwick (Cariba Heine) are three adolescent girls who become stranded on Mako Island. Upon discovering a concealed underwater pool linked to the ocean, they undergo a transformation into mermaids, each endowed with distinct aquatic abilities: Emma possesses the power to freeze water, Cleo can manipulate its form and volume, and Rikki has the ability to heat it to boiling. They recruit Cleo’s friend Lewis McCartney (Angus McLaren) to assist in deciphering their new condition and safeguarding their secret. The narrative combines elements of teenage drama with supernatural themes as they learn to manage their powers.

The central plot introduces Louise Chatham (Christine Amor), a former mermaid who acts as a mentor to the trio. Zane Bennett (Burgess Abernethy) becomes fixated on locating the "sea monster" after spotting Emma’s tail. Marine scientist Dr. Denman (Lara Cox) pursues the girls following Lewis's inadvertent submission of a genetic sample to her laboratory. Initially, Zane collaborates with Dr. Denman to capture the mermaids but later aids in their release when their abilities are temporarily nullified during a lunar eclipse.

Template:Episode list Template:Episode list {{Episode list ... [Episodes continue similarly with concise summaries emphasizing key plot points relevant to character development and overarching storylines.] ... }}

No. overall	No. in series	Title	Directed by	Written by	Original air date	Production code

Series 2 (2007–08)

During a rare planetary alignment at Mako Island's moon pool, the girls experience a significant enhancement of their abilities. This season introduces Charlotte Watsford (Brittany Byrnes), who relocates to the Gold Coast, develops feelings for Lewis, and becomes the fourth mermaid after visiting the moon pool. Claiming to be superior, Charlotte emerges as an antagonist, leading to a climactic confrontation in which she permanently loses her mermaid powers.

Romantic relationships are further explored: Cleo ends her relationship with Lewis due to his possessiveness; Lewis briefly dates Charlotte before returning to Cleo. Meanwhile, Rikki and Zane rekindle their romance, and Emma confides her mermaid identity to Ash (Craig Horner). Ultimately, Lewis reaffirms his loyalty to the girls, particularly Cleo.

Template:Episode list Template:Episode list Template:Episode list Template:Episode list Template:Episode list Template:Episode list Template:Episode list Template:Episode list Template:Episode list Template:Episode list Template:Episode list Template:Episode list Template:Episode list Template:Episode list {{Episode list │ Title │ Irresistible │ │ OriginalAirDate │ Template:Start date\ │ │ EpisodeNumber │41 │ │ EpisodeNumber2 │15 │ │ ProdCode │215 │ │ DirectedBy │ Colin Budds │ │ WrittenBy │ Chris Anastassiades │ │ ShortSummary │ Zane obtains ambergris believed to attract mermaids; Nate unknowingly uses it, drawing the girls dangerously close and risking exposure of their secret. │ │ LineColor │ 00AAFF │ }} {{Episode list │ Title │ Double Trouble │ │ OriginalAirDate │ Template:Start date\ │ │ EpisodeNumber │42 │ │ EpisodeNumber2 │16 │ │ ProdCode │216 │ │ DirectedBy │ Colin Budds │ │ WrittenBy │ Simon Butters │ │ ShortSummary │ Lewis experiences nightmares about revealing Cleo’s secret. Elliot asks Kim out while Emma suspects Rikki’s secret meetings with Ash relate to an award plan. │ │ LineColor │ 00AAFF │ }} {{Episode list │ Title │ Moonstruck │ OriginalAirDate │ Template:Start date\ │ EpisodeNumber │43 │ EpisodeNumber2 │17 │ ProdCode │217 │ DirectedBy │ Colin Budds │ WrittenBy │ Philip Dalkin ├───┬───────────────────────────────────────────────────────────────┤ Short Summary Ash surprises Emma with dinner on a full moon night, triggering chaos as moonstruck Cleo and Rikki nearly reveal their secret before Lewis intervenes. Absent: Brittany Byrnes as Charlotte Watsford Line Color #00AAFF }} {{Episode list Title The Heat is On Original Air Date 25 January 2008 Directed By Colin Budds Written By Philip Dalkin Production Code 218 Short Summary To mark one year as mermaids, tensions arise between Emma and Rikki due to misunderstandings involving Zane and Ash, threatening their planned celebration on Mako Island. Meanwhile, Lewis feels remorse for neglecting Charlotte. Line Color #00AAFF }} {{Episode list Title The Gracie Code, Part One Original Air Date 1 February 2008 Directed By Colin Budds Written By Max Dann Production Code  219 Short Summary Lewis uncovers Max Hamilton's research on Mako Island connecting past mermaids including Gracie. Max identifies Cleo as a mermaid and entrusts his findings to Lewis under promise of secrecy. Absent: Claire Holt as Emma Gilbert Line Color #00AAFF }} {{Episode list Title The Gracie Code, Part Two Original Air Date  8 February 2008 Directed By Colin Budds Written By Anthony Morris Production Code  220 Short Summary After Charlotte steals Max’s research reel, the girls discover footage of Gracie as a mermaid. Meanwhile, Ash nearly uncovers Emma's secret while trying to support her. Line Color #00AAFF }} {{Episode list Title And Then There Were Four Original Air Date  15 February 2008 Directed By Colin Budds Written By Susan MacGillicuddy Production Code   221 Short Summary During a full moon dive at Mako Island, Charlotte learns from Max about her grandmother’s mermaid heritage and transforms into a mermaid herself. Line Color #00AAFF }} {{Episode list Title Bubble, Bubble, Toil and Trouble Original Air Date  22 February 2008 Directed By Colin Budds Written By Sam Carroll Production Code   222 Short Summary The four girls grow closer through their school volleyball team but remain cautious about Charlotte wielding all their powers as she declares herself "super mermaid." Line Color   #00AAFF }} {{Episode list Title Reckless Original Air Date   29 February 2008 Directed By   Colin Budds Written By   Max Dann Production Code   223 Short Summary   Rejecting assistance in managing her powers, Charlotte recklessly uses them publicly causing damage and conflicts that jeopardize the mermaids’ secrecy. Line Color   #00AAFF }} {{Episode list Title   Three's Company Original Air Date   7 March 2008 Directed By   Colin Budds Written By   Sam Carroll  Production Code   224  Short Summary   Charlotte dominates planning for Lewis’s birthday party alienating Rikki and putting their secret at risk until the others intervene and exclude her.  Line Color #00AAFF }} {{Episode list  Title  Sea Change  Original Air Date 14 March 2008  Directed By Colin Budds  Written By Robert Armin  Production Code 225  Short Summary Charlotte distances herself from the group and manipulates Lewis against Cleo, sparking conflict that ends with Charlotte losing favor as Lewis reunites with Cleo after rescuing her from danger.  Line Color #00AAFF }} {{Episode list  Title Unfathomable  Original Air Date 21 March 2008  Directed By Colin Budds  Written By Chris Roache  Production Code 226  Short Summary A powerful full moon threatens permanent loss of powers; after confronting Charlotte who uses her abilities against them, she loses her powers forever as secrets come to light. Note: Final appearances of Claire Holt, Brittany Byrnes, and Craig Horner  Line Color #00AAFF }}

No. overall	No. in series	Title	Directed by	Written by	Original air date	Production code

Series 3 (2009–10)

The third season begins by focusing on Cleo and Rikki as they adjust to Emma's absence during her family trip. This series introduces new central characters: Bella Hartley (Indiana Evans), a mermaid with the unique ability to transform water into gelatine and a talented singer, alongside Will Benjamin (Luke Mitchell), an expert diver delving into the mysteries of Mako Island. Will unintentionally activates a power that makes the water hostile toward mermaids. Concurrently, after Rikki ends their relationship, Zane attempts to take advantage of the moon pool.

{{Episode list

No. overall	No. in series	Title	Directed by	Written by	Original air date	Production code
Title = Happy Families	OriginalAirDate = (UK)	EpisodeNumber = 59	EpisodeNumber2 = 7	ProdCode = 307	DirectedBy = Jeffrey Walker	WrittenBy = Max Dann	ShortSummary = Don brings his new partner Sam to meet his daughters, causing family friction that Kim exploits for personal gain. Bella seeks employment at the café, but Zane prefers Sophie for the role.	'Absent: Angus McLaren as Lewis McCartney

{{Episode list ... [Episodes continue in similar compressed format] ... }}

Note: Claire Holt exited the series to pursue filming for Messengers 2: The Scarecrow. This season marks the addition of Indiana Evans and Luke Mitchell to the principal cast. Angus McLaren makes his last regular appearance in the episode titled "To Have & to Hold Back".

Compilation TV films

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Title	Original air date

External links

Comprehensive episode list on the Internet Movie Database