26 October 2009 (UK)
Cleo and Rikki face their final year of high school without Emma. They make a new friend in Bella and meet new boy Will – and encounter a strange new force on Mako Island that turns water against them.
Cleo and Rikki are about to face their final year at school together without Emma, who's gone overseas. They're confident they've overcome the affect of the Full Moon and know everything about Mako Island and its magic. Zane surprises Rikki with an offer for her to join him as a partner in a new upmarket cafe, while Lewis is taking his relationship with Cleo a little too comfortably. When Will, a boy with remarkable skills underwater stumbles upon the Moon Pool, he encounters a strange water force and is knocked unconscious. That night, at the opening of the new cafe, Rikki and Cleo meet Bella, a new girl who helps Rikki out of a tricky situation by stepping in to sing in Nate's band. In a break outside, Rikki's attacked by water and dragged out to sea. Bella sees this and joins Cleo to rescue Rikki. Cleo's shocked to find Bella's a mermaid too! Rikki's saved from the encounter but they find the new boy Will in the Moon Pool. The girls realize something has changed on Mako Island, and it appears Will is now on the trail of their magic and secret.
- JuiceNet Café is now replaced with Rikki's Cafe.
- The colors of their tails changed from bronze, to orange gold.
- New version of "No Ordinary Girl" sung by Indiana Evans and new opening intro.
- Claire Holt (Emma Gilbert) is no longer credited.
- This episode marks the first appearance of the water tentacle.
- As Rikki and Zane hand out leaflets advertising the opening of Rikki's Cafe, the guitar instrumental that plays is the same one featured in 2 episodes of Season 1, "Metamorphosis" and "Catch of the Day".
- Claire Holt left the show to film Messengers 2: The Scarecrow. Emma has been explained away as traveling the world with her family and was never seen or mentioned again. First appearances of Indiana Evans and Luke Mitchell.
- When the water tentacle gets Rikki it gets her head first but when you see her in the water it's the opposite.
- Don Sertori: (To Lewis) Hands off my pizza, my fishing magazine, and my daughter.
- Lewis: (To Don) That's warm reception I get from you Mr.S. I just can't stay away.
- Rikki: (To Bella) Nice Tail.
- Bella: (To Rikki) Likewise.
- Cleo: It's about tonight. It's full moon. Werewolf time.
- Lewis: Came on, you guys got that sorted.
- Cleo: Maybe. I mean it's gonna be little people there, and if we start howling at the moon.
- Rikki: If everyone isn't howling at the moon by 10 then I have failed.
- Rikki Chadwick - Cariba Heine
- Cleo Sertori - Phoebe Tonkin
- Isabella Hartley - Indiana Evans
- Lewis McCartney - Angus McLaren
- Will Benjamin - Luke Mitchell
- Zane Bennett - Burgess Abernethy
- Nate - Jamie Timony
- Jason - Ben Timony
- Lead Guitarist - Jarreau La Castra
- Bass Guitarist - Remy Hill
- Surfer #1 - Clinton Stewart
- Surfer #2 - Jordan Patrick Smith
- Surfer #3 - Rick Mitchell
- Donald Sertori - Alan David Lee