Ep 5. Something Fishy

Cleo's emotions are all over the place after breaking up with Lewis. When she, Emma, and Rikki investigate a nearby marine park, they discover that the park's owner, Dr. Denman, is studying the effects of the full moon on the local marine life. They accidentally get caught in her net and discover that they are immune to the full moon's effects due to their mermaid powers. But when Dr. Denman sees them transform back into humans and realizes what they are, the girls must find a way to keep their secret safe. Meanwhile, Cleo meets a strange boy at the marine park who seems to have a mysterious connection to the water.