As if being a teen weren't hard enough, the three gals in this Australian fantasy series must cope with the added burden of growing a giant fin and transforming into mermaids whenever they come into contact with water -- a fact they try to hide.
Under the influence of a Full Moon, the girls' powers are hugely enhanced and they wreak havoc on Lewis in his boat. The next day the girls realise they still need Lewis.
Emma uses her new powers to help Elliott win at soccer. Lewis decides to test the girls' increased powers. Cleo has had enough of Lewis' smothering and dumps him. Lewis meets Charlotte and they bond.
Zane's back in town and still in love with Rikki. He works out she's still a mermaid and tries to win her back. Cleo becomes suspicious of Lewis spending time with Charlotte.
Rikki comes to stay at Emma's house and stirs up the family unit. In trying to compete with Rikki, Emma tries to rebel and throws a party. Nate uses Lewis to make a play for Cleo.
Lewis finds an old book on mermaids and tests out a potion recipe on the girls. Cleo tries to get Don and her Mum together by using her powers to grant him a wish. Realising it's not what he wants, she finally accepts the situation.
Everyone is shocked when Cleo is fired at the Ice Cream Stand, and even more so when Lewis takes her place! Rikki and Emma strike back at him but end up going too far.
Zane has an argument with a man in a trailer park but little does he know it's Rikki's dad. Rikki has to overcome her shame about her background and introduce her dad to Zane.
Emma meets Ash - a handsome horse riding instructor. A horse falls ill and Emma must use her powers to fix it. Lewis accidentally invites both Charlotte and Cleo to an awards dinner.
Cleo is failing at school and is assigned a tutor - Charlotte. Cleo wants Lewis back but her attitude to Charlotte only drives him further away. Cleo discovers Lewis and Charlotte kissing.