When Ester overhears her grandmother talking about the ultimate beauty product - knotted kelp - she decides she wants some for herself. The girls won't give up in trying to find this old algae…
The Starfish Grandmother and her starfish, Pointer, are staying at the Starfish Palace, much to Ester and Spikey’s excitement. Ester and Spikey overhear the Starfish Grandmother telling the Starfish Queen about some old algae, like knotted kelp, which is apparently the secret to beauty. When Ester tells Polvina and Tubarina about it, Tubarina is keen to find some knotted kelp for herself as well. Ester and Tubarina are about to head to Rainbow Reef to find the kelp, but Polvina tells them not to, telling them that beauty comes from what they do, not what they look like. Ester and Tubarina initially decide not to get the knotted kelp, but they give into their desire for beauty and that being obsessed with beauty makes them blind to the beauty all around them. Polvina believes that Ester and Tubarina won’t try to get the algae, but then realises that they probably won’t listen to her.
The girls encounter each other swimming to Rainbow Reef, but just as they get there, they find lionfish guarding the algae. They decide to get Lia to help them with the lionfish, but Polvina finds that she is obsessed with beauty as well. Lia convinces the lionfish to let them get some of the algae, which they do. Just as Ester, Tubarina and Lia are fighting over a piece of the algae, they find some other girls nearby; Lia reveals that she told them about the secret. Polvina tries to explain to Ester and Tubarina that their obsession with beauty has made them greedy. Ester and Tubarina are initially convinced to abandon the algae, but just as Polvina thought, they decided to take it anyway.
Ester and Tubarina put the algae on their faces before they go to sleep. When they wake up the next morning, they find that their faces have turned orange, much to their horror; the same happens to Lia and the other girls as well. Polvina struggles not to laugh at the sight before assuring them that it won’t last forever. Right as that moment, Lia and the other girls find them and they swim away. At the Starfish Palace, the Starfish Grandmother giggles at the sight before she reveals that she didn’t want Ester or Spikey to know about it because she didn’t want them to go near the lionfish. When Ester points out that it wasn’t the problem, the Starfish Grandmother reveals that the algae is meant to be used on starfish. As Polvina sardonically compliments them on their beauty, Ester and Tubarina attempt to put some of the algae on her face, but they quickly find themselves being chased by Lia and the other girls…
- In the official synopsis, the "ultimate beauty product" is erroneously stated to be a rare red seaweed.
- Coincidentally, "a rare red seaweed" is the subject of the episode The Seaweed Potion.