Ep 3. Catch of the Day

In "Catch of the Day," the third episode of the first season of H2O: Just Add Water, best friends Cleo (Phoebe Tonkin), Emma (Claire Holt), and Rikki (Cariba Heine) are back dealing with the trials and tribulations of being teenage mermaids.

The episode opens with the girls enjoying a day at the beach with Cleo's little sister, Kim (Cleo Massey), who confesses that she's been failing science class. Emma, who dreams of becoming a marine biologist, offers to help Kim study for her science test, but the girls are soon distracted by a fisherman named Mick (Craig Horner) who's caught a giant fish. Intrigued, they decide to follow him to see the fish up close, but as they're walking, the girls suddenly feel weak and disoriented. Mick seems unfazed and walks away, but the girls are left to wonder what's wrong with them.

As they recover, Emma mentions that the girls might be suffering from the effects of a nearby marine park, which uses a frequency to drive away sharks from their area. When they return to the marine park to investigate, they find that the frequency is hurting them, too. Emma hypothesizes that because they're mermaids, they're more sensitive to the frequency.

Their investigation leads them to the park's owner, Dr. Denman (Lara Cox), who believes that the girls are the key to unlocking the mysteries of the ocean. Dr. Denman offers to hire Emma as a junior marine biologist, but when Emma refuses, Dr. Denman becomes suspicious of the girls and begins to investigate them.

Meanwhile, Kim's science test approaches, and Emma struggles to help her study while keeping their mermaid secret safe. She takes Kim to the marine park to show her the fish and inadvertently leads her sister to Dr. Denman's secret lab, where the girls discover that Dr. Denman is researching the effects of the park's frequency on marine life. When Dr. Denman finds them, the girls try to make a run for it, but Cleo is caught in a net and Emma and Rikki are forced to leave her behind.

In the end, Emma and Rikki hatch a plan to break into Dr. Denman's lab and rescue Cleo, but they're caught by Dr. Denman and her men. Just as things seem hopeless, Cleo unleashes a powerful wave that breaks the net and frees her. Together, the girls use their powers to escape and return home, where they vow to keep their secret safe.

"Catch of the Day" is a thrilling episode that further explores the girls' powers as mermaids while also delving into the dangers of marine life and the politics surrounding animal conservation. The episode is full of suspenseful moments and action-packed scenes, as well as heartwarming moments between the main characters. It's a perfect introduction to the world of H2O: Just Add Water for new viewers and an exciting continuation of the story for fans of the show.