Mia and Sara are outside, Sara having trouble focusing on learning more about Centopia due to the heat. Sara suggests they head to Stella's place for ice cream, to Mia's surprise. Sara explains that since she promised her mother to return to school, she has to learn to be comfortable out in public anyways. Mia and Sara head into town once more, with Mia noting that things seem busier than last time. On their way, they find that they have to get past a group of tourists. Mia suggests they head home if Sara is uncomfortable, but Sara instead suggests they take a detour to avoid anymore people. They take a break by a fountain, and Sara realizes where they are, an old fountain where cats like to gather.
Mia's bracelet begins to glow, and asks if Sara will be okay by herself for a few minutes. Sara says it's fine, and Mia promises to be back soon.
Mia heads to Centopia, bumping into Mo on the way. Mia comments on a diamond Mo intends to give to Yuko, but Mo insists it's not simply a present. Mia and Mo meet up with Yuko, who is entertaining Onchao and Kyara by blowing soap bubbles. Mo gives Yuko the diamond as a price for being the best unicorn guardian in Centopia. Yuko asks how many times this award has been given, to which Mo sheepishly admits this is the first time. Mia reveals the latest oracle, and the group realizes it can only refer to the Rainbow Island.
As the group heads out, Kyara feels sad at being left behind, and decides to follow the group.
At the villains' lair, Drakon is umimpressed with Dax and Gargona's latest plan to sneak in and replace Kyara with a fake. A bug that was spying on the group reports to Dax, and he and Gargona head out.
Onchao unlocks the Rainbow Island, and Yuko stands guard while Mia, Mo and Onchao prepare to travel to the island. Kyara suddenly shows up, and since they have to look after her, they decide to bring her along to the island. Arriving at the island, Kyara is amazed at being able to speak like the elves. Onchao soon meets up with his friend Flair, who is excited to meet Kyara. Garnivera shows up, who takes an interest in the heart shard Mo wears around his neck.
Meanwhile, Yuko looks at her diamond, as Gargona and Dax pull a sneak attack and tie her up.
Flair wonders why Onchao doesn't seem too enthusiastic about playing with bubbles the way Flair and Kyara does, and Onchao admits that he had hoped to spend some time alone with Flair. He ends up going off on his own, with Flair assuring Kyara that he'll come back. Garnivera explains that she knows about what is happening in Centopia, and tells them about a crystal like the one Mo has. However, he warns Mia and Mo that they mustn't touch it.
Gargona and Dax arrive at the island, and begin to search the area.
Garnivera explains that removing the crystal might destroy the Rainbow Island. Garnivera explains more about the legend of Centopia's heart, and how the heart shard that landed on the island is what gave more life to the island. Onchao, not knowing this, happens to find the shard, and decides to take it with him, damaging the rainbow source. Onchao realizes he's made a mistake, and he, Flair and Kyara go to return it.
Mia and Mo come across the villains at the source, and assume they're the ones who removed the source. Yuko manages to free herself, and hurries over to the island to help her friends. Shortly after Yuko arrives, the unicorns show up. Yuko and Onchao manage to fight off the bad guys, despite being outnumbered, before Onchao returns the heart shard, which begins restoring the island to how it was. Onchao admits to Garnivera what he did, and apologizes for his actions to both Flair and Kyara.
Mo is unsure what to do, since they still need the shard, but can't remove it. Mia suggests that since it was the love within the shard that brought such light to the island, that there might be something else that can be substituted for the shard. The diamond that Mo gave to Yuko manages to keep the island in its beautiful state, although Mo and Yuko deny there's anything more behind it.
Mia has to return home, and discovers that a group of tourists have gathered by the fountain where Sara was earlier. The cat Sara was petting earlier leads Mia to Sara, who asks where Mia went, and Mia reminds her that she really does disappear when going to Centopia. Having calmed down, Mia asks if Sara still wants to go get ice cream, and they decide to buy some popsicles from a shop they passed by earlier on the way home instead.
Tropes
- The Power of Love: Turns out the Rainbow Island is powered by this.
- Take a Third Option: The rainbows of Rainbow Island are created from the heart shard in the rainbow source, and if removed, the island will lose its magic. However, the elves need that heart shard in order to save Centopia... Mia then suggests that since Garnivera said it was the strong love contained within the heart shard that gave the island its power, maybe they could use something else as a substitute. The diamond Mo gave Yuko earlier in the episode manages to work as a replacement for the heart shard.
