Veridia gives Ondina a special job befitting her talents - teaching the pod's little mermaids, one of whom goes off on her own and gets into trouble.

When marine park workers are sent to investigate the sea monster, the mermaids most create a credible explanation to stop further inquires.

Weilan casts a knowledge transference spell on Zac to help him pass a biology test. But more than just science facts transfer from her body to his!

When Evie tries using her new moon ring to magically finish her chores, things quickly get out of control. Joe makes an upsetting announcement.

Weilan comes up with the idea of using a Chinese Puzzle Box to trap the sea dragon. Cam panics when Carly suggests they take dance lessons.

Evie's moon ring lesson with Ondina takes an unexpected turn. At the Marine Park, Mimmi discovers the real reason for a rescued dolphin's distress.

Zac begs Weilan to teach him an Eastern spell that he plans to use against the dragon. Mimmi and Ondina cover for David at the Ocean Cafe, but they encounter problems with Joe and a water ball.

On the eve of the full moon, Mimmi and Ondina defy Veridia's order of watching the hatchlings. Evie becomes suspicious when she spots Zac and Weilan meeting in secret again.

Feeling guilty for Evie's loss, Weilan runs away. Mimmi and Ondina try to restore Evie's tail.

Zac finds a shell in Mako. Without realizing it's magical, he makes a wish, sending the mermaids five years back in time.

While teaching the younger mermaids how to walk on land, Ondina and Weilan lose a mermaid in Mako that soon, runs into Chris and Karl on the beach.

Mimmi and Chris go on their first date and Ondina does everything to protect her. Cam makes changes to the Café.

Mimmi's visions of a mysterious mermaid lead her to the inescapable conclusion that she must be her and Zac's mother, Nerissa. Upon learning their mother is fabled Nerissa, Weilan recounts how their mother helped defend the Eastern pod from a rebel mermaid named Aurora but never returned after going to face her alone. Zac advises caution but Mimmi is determined to find out what happened to her. In her haste, Mimmi unknowingly summons the Water Dragon which pursues her only to vanish as just suddenly as it appeared. Meanwhile, Carly is frustrated by Cam pulling double ...

Mimmi helps Ondina come up with an exciting new lesson for the little mermaids using an accelerated growth spell. With the school board undertaking a review of Rita's principalship, Ms Trumble make it no secret that she is out for the job herself. Rita's all but assured to retain the position but after mistakenly drinking tea made from the growth accelerator, Rita begins to age rapidly. Luckily Rita knows the recipe for the reversal potion - she just can't remember the final ingredient. Zac and Evie's attempt to spend a quiet day together keeps getting interrupted. ...

A priceless artifact recovered by a deep-sea treasure hunter provides a clue as to how the mermaids can defeat the water dragon.

The vision reappears to Mimmi and Zac, this time speaking to them. Weilan learns a new detail about the dragon legend that suggests Nerissa is alive.