H2O: Just add Water

Cleo and Emma meet new girl, Rikki, and find themselves stuck on Mako Island where they are transformed into mermaids. As well as growing tails, the girls find they have powers over water.

Annoying Miss Popularity, Miriam, is having a pool party that the girls don't want to miss. But it's a risky activity for three mermaids: their secret could be out. Spurned by Lewis, Rikki discovers her mermaid power is to boil water at will!

When Emma and Rikki save a sea turtle from a fishing trawler's net, they are mistaken for sharks. A shark hunt ensues. Cleo, getting over her fear of water, saves another turtle, but she is trapped.

Determined to live her life as normal, Cleo confronts her fears and lands a job at the Marine Park, helping out to feed the dolphins. Despite her precautions, she gets splashed and, just as she’s about to turn into a mermaid, a mysterious Old Woman, Miss Chatham, comes to her rescue.

Kim reads Cleo’s diary and finds evidence of mermaidness. She spies on the girls and decides Miriam is the head mermaid. Miriam and Cleo enter the Queen of the Sea contest where Kim tries to prove her theory but only succeeds in upsetting Miriam.

Rikki gains an admirer in Emma's younger brother Elliot when she saves him from drowning. She lets him down hard causing him to run away and hide in the fernery. The girls find him just as the watering system is about to start.

The effects of the full moon turns Emma into a carefree, wild mermaid. At her father's birthday party she's the opposite to her usual, organised self. Can the other girls stop her before all is revealed?

A charismatic newcomer, Dr Denman, tempts Lewis with the promise of scientific fame and fortune. Will he abandon his friends and risk their secret, all in the name of science?

Rikki uses her abilities as a mermaid to earn some quick cash but when she accidentally becomes involved in a fish smuggling operation she sets out to get her revenge.

Zane tries to impress his dad by entering in the local film competition, filming his attempt to break his Dad’s windsurfing record around Mako Island. He gets into trouble with sharks and unbeknownst to him, is saved by mermaid Rikki.

Emma trains Byron for the swimming competition. At first they get along well and even share a kiss, but too soon Emma becomes the training dragon. Byron fires Emma but when he wins the comp he tries to hug her and she recoils.

The full moon strikes Cleo, turning her into a magical siren, attracting all the young males in the vicinity. Cleo enjoys the attention and is encouraged to sing for them, but a concert at the Juice Bar as the moon sets reveals her truly awful voice.

When the mysterious old woman’s boat and home is declared unseaworthy Emma invites her over to stay. Zane gets trapped on the sinking boat and Emma tries to save him.

Cleo’s dad plans an embarrassing surprise party for her birthday so she escapes to Mako Island. Zane and Lewis almost spot her there on their expedition to catch the sea monster.

Emma is put in charge of managing the juice bar. Miriam decides to cause trouble and cuts the power to the cool room, then is unwittingly frozen by Emma who uses her powers to fix the freezer. Will the girls be able to thaw Miriam out?

A dolphin at Sea World will only eat from Cleo’s hand and when she has to sneak out to feed him, everyone thinks she has a boyfriend.

A rainy day traps the girls inside. In an effort to "play sick" the girls create a situation where their families become part of a dire medical emergency.

Under the effects of the full moon Rikki goes crazy, boiling dry everything. She runs away to Mako where she meets Zane and kisses him.

Cleo and Kim are fighting like crazy and Cleo is pushed to breaking point. Then cousin Angela comes to stay and things just get worse. Cleo realises there are more challenging things than an annoying sister.

Emma and Cleo help Lewis catch a huge fish in the fishing competition leading the judges to suspect he's a cheat. Meanwhile Zane and Rikki are stuck together on a balcony of a fancy hotel where after much argument, they kiss again.

Zane thinks Miss Chatham holds the key to the sea monster. Emma needs a change so dyes her hair red. While Zane gets closer to the secret, he also gets closer to Rikki. Zane dives to Miss Chatham’s boat and sees a mermaid!

Emma and Cleo find out Zane and Rikki are an item and force her to choose - him or them. When Zane appears to side with Harrison over the Mako island development Rikki’s decision is clear. Now it’s Zane’s turn to make a choice.

The girls discover a necklace for sale identical to Miss Chatham’s. Miriam causes a stir by buying it - then throwing it in the water. Rikki faces a choice whether to take the necklace and reveal her mermaidness to Zane.

Lewis thinks he’s found a way to control the girl’s mermaidness. The school dance brings all our heroines’ ‘boy issues’ to the surface.