Summer vacation has begun, and Mia is greeted by her grandfather, Renzo, as she arrives with the train at the train station. As they are driving to the farm in Mia's grandfather's car, Mia hears meowing and the grandfather asks her to open a box. The box contains a kitten, which Mia names Mimi. Mia is excited about seeing the other animals at her grandfather's farm, and her grandfather shows her around, introducing her to the various animals. Mia also meets Mario, a boy who has been helping out at the farm in the summer. Renzo shows Mia the room she'll be staying in during her stay at the farm, and heads downstairs to give Mia some time to get used to her new room. Mia notices her bracelet glowing, and checks her book, which warns of a new threat.
Mia arrives in Centopia, commenting that it's even more beautiful than she remembered. Mia meets up with Yuko and Mo, reuniting with her friends. Mia notices that they're not wearing their water shooters, with Mo explaining that they no longer need them with Panthea gone. Mia soon meets up with Raynor, Mayla and Phuddle, the latter whom is working on some adjustments to the water barrier. Mia asks about Onchao, and the king and queen reveal that he is now living amongst the other unicorns.
Mia flies over to see the unicorns, and meets up with Lyria. Mia soon finds Onchao, who seems to be having an argument with another unicorn foal. The other unicorn foal, Esco, seems to find it unfair that Onchao is the only one around with wings. Elsewhere, a mysterious island seems to be approaching Centopia. Mia tells Onchao that she knows what it is like to feel like one doesn't fit in, but that since she was able to make two really great friends at her school, she's sure things will work out. She receives a signal from Yuko and Mo, and goes to see what's going on.
As the strange island reaches the shore, an elf called Rixel shows up and introduces himself. Since he seems nice, albeit a bit eccentric, Raynor welcomes Rixel and his circus to Centopia. Mia decides to show it to Onchao as well, and flies off to find him. As Rixel begins showing the king and queen around, he tells his rubber-like monkey companion to go search for something. Mia finds Onchao and tells him to come see the circus, when they come across the monkey, who has eaten too many berries. Onchao helps the monkey, which then takes an interest in Onchao's wings, before running off.
Meanwhile, Gargona is expressing her frustration with being trapped in Centopia, and notices Rixel's island, deciding to sneak onboard in hopes of getting away from Centopia. A trio of elf girls unknowingly carry the barrel Gargona is hiding in onto the island. Rixel starts asking Raynor and Mayla about Centopia's unicorns, and whether there is any way to see them. One of Phuddle's inventions suddenly sends Phuddle flying into the back of the island where Rixel claims to be keeping his animals. Phuddle comes across a large dragon, but Rixel assures them that the dragon, Gurga, is merely one of his performers and not a threat.
Mo and Yuko start to express some suspicions about Rixel, when the monkey returns to report to Rixel. Spotting Mia approaching on Onchao, Rixel goes to try to befriend them, but noticing that Onchao doesn't seem to like Rixel, Mia realizes that the riddle meant that Rixel is hiding something and the two fly away. Rixel tells everyone else to leave, claiming to have work to do. Gargona comes out of her hiding spot, and follows Rixel as he heads deeper into the caves on the island. He approaches a large tub of green fluid, reporting to his master. An intimidating dark elf speaks to him through an image in the fluid. Rixel reports that he saw a unicorn similar to the dark elf's description, except it was only a foal and didn't have a black coat. The dark elf muses that it can't be Ono, but that it might be one of his descendants. The dark elf tells Rixel he has until the next full moon to capture the winged unicorn, if he wishes to become a dark elf and come with him to Dystopia. Gargona makes her presence known, and the dark elf reveals that he sent Panthea to Centopia a long time ago, but she failed in her mission. He recruits Gargona, telling her to assist Rixel, and that she'll be allowed to return to Dystopia if she succeeds.
At the elf palace, Mia informs Yuko and Mo of the riddle, and they agree that something seems suspicious about Rixel. Mia has to return home, and returns to her own world. Heading outside, Mia goes to properly introduce herself to Mario.
- All of the Other Reindeer: Onchao is having trouble getting along with some of the other unicorn foals due to being the only one with wings.