H2O: Just Add Water - Season 1 (2006)

Cleo convinces Emma to go ahead with her traditional slumber party, with some unexpected results.

After discovering Cleo's Mermaid diary, Cleo's little sister is determined to save the Gold Coast from the 'evil Mermaids'.

When Rikki drags Elliot from the surf Emma is worried about exposure, but Rikki is more worried about the crush he's developed.

Cleo receives a mysterious warning: do not stare at the full moon, not even its reflection. Emma is more concerned about her father's surprise birthday party.

Lewis gets a job as lab assistant to the beautiful Dr Denman in an effort to find more answers for the girls, but they're not convinced he can keep their secret.

When Cleo's pet fish passes away, Rikki tries to cheer her up.

Not convinced an interview with Emma's mum will win the short film competition, Rikki decides to get some award-winning shark footage. Zane recruits Lewis to re-enact a record windsurfing run.

Byron asks Emma to coach him for the school swimming carnival. Rikki vents her frustration at Lewis's apparent disinterest in the girls as anything other than specimens.

The moon is full again, and Cleo feels its powerful effects, singing a siren song that has the boys all over town swooning.

Emma stumbles upon the mysterious Elder who knows more about what it means to be a Mermaid than the girls themselves.

Why is Cleo so desperate to avoid celebrating her 16th birthday? Zane recruits Lewis in his hunt for the 'sea monster'.

Emma loves her job at the café, at least until she's left in charge of new employee Rikki, who doesn't take kindly to her authoritarian ways.

Zane seeks assistance from Cleo in his hunt for the sea monster that saved him, which leads to her family believing that Zane is Cleo's boyfriend.

When a thunderstorm threatens to out the girls as mermaids, they pretend to be sick, but their lie attracts the attention of their parents.

The full moon is back, and this time it's Rikki's turn to fall under its sway but she loses control of her powers and flees to Mako Island.

Cleo's cousin Angela is a force to be reckoned with, and while Cleo's dad mistakes her for a model of maturity, she proves to be a reckless wild child.

Lewis enters a fishing contest, and Cleo uses her powers to help him win, but her plan backfires when Lewis is accused of cheating.

Emma dyes her hair red, with decidedly mixed results; Zane's quest for the sea monster leads him to Miss Chatham and her old homestead.

Romance heats up between Rikki and Zane, and Cleo and Emma find out, making Cleo demand that Rikki choose between her mer-friends and her new boy.

When Rikki spies a locket with an uncanny resemblance to Miss Chatham's in a jewelry shop, Zane doesn't understand her desperate desire to possess it.

Emma and Cleo hope that Byron and Lewis will ask them to the school dance, but Lewis is left to ponder the significance of science vs. magic.

Emma refuses to accompany her family on their annual vacation; Dr. Denman's return brings Zane even closer to learning the secret of his sea monster.

Their mermaid identities no longer a secret, Cleo, Emma and Rikki must evade a trap being laid by the devious Dr. Denman.