Mimmi and Sirena prepare a potion that helps the user to look younger. Rita applies some before a school excursion to the Marine Park, accompanied by Dr. Ross, the park's handsome Director. Rita is unaware that Ondina accidentally altered the potion, which now makes her act younger as well. Evie and Zac have to move fast to stop the excursion turning into a disaster, while Rita behaves like a young child, threatening to reveal the truth about mermaids when she decides to go for a swim.
Elenco: Allie Bertram , Isabel Durant , Chai Hansen , Linda Ngo , Gemma Forsyth .