Mia has begun practicing for the tournament with Sapphire. Since there will also be jumping over obstacles, Mia suggests they might need something for Sapphire to practice that aspect of the competition. Renzo brings the group to a nearby shed that hasn't seen any use, suggesting they use some materials from it to make some improvised obstacles for Sapphire to practice with. Inside the shed, the three find a hedgehog that was trapped inside, and Mia brings it back to the house to feed it while Renzo and Mario work on preparing the obstacles. After setting up their improvised obstacle course, Mia tries to encourage Sapphire to jump over the obstacles and not be nervous because of his previous bad experiences with Violetta. Sapphire manages to successfully jump over an obstacle, and Mia congratulates him as her bracelet begins glowing. She excuses herself to take a break, and heads back inside.
Mia arrives in Centopia and meets up with her friends. Phuddle claims to have figured out how the four rings will fit together, but gets distracted. Mia tells her friends about the riddle, and they quickly come to the conclusion that the fourth and final ring must be in Panthea's castle. Onchao is concerned when the group realize that the ring being in the castle means Panthea must at some point have fought Ono, and won. As the group begin making their way towards the castle, they are spotted by Tuquito.
Tuquito returns to report to Rixel as Rixel and Gargona are talking to their master, who is not pleased with the lack of progress in their mission. Rixel attempts to figure out what Tuquito is saying, his master eventually figuring out that Tuquito is referring to Panthea. The bad guys head out to go to Panthea's castle.
Mia and her friends arrive near what used to be the enclosure where Panthea kept the captured unicorns, Mia commenting on how much the place has changed since Panthea's defeat. Mo finds Panthea's mask and cloak, and decide to take them along in case they prove useful as hinted by the riddle. Meanwhile, Rixel and Gargona are also headed towards the castle, with Rixel telling Gurga and Tuquito to stay behind. Mia and her friends find the source of the fog that used to surround the area, and manage to slip into the tunnels below the castle. Rixel and Gargona also venture through the tunnels, with Gargona leading the way.
Mia and her friends come across Panthea's cat, Ziggo, who is wandering the tunnels. Gargona leads Rixel to a hidden vault, and reveals that she once secretly followed Panthea there and learned how to open it. Gargona opens the vault, containing the ring. Before Gargona can warn him, Rixel steps into a trap.
Still making their way through the tunnels, Yuko wonders exactly where the ring is, when they hear laughter in the distance. Gargona takes Rixel through a detour, just because she wants to sit in Panthea's old throne for just a moment. Onchao and Mia walk up to them, and try to talk Rixel into giving them the ring. Mo takes out Panthea's mask, figuring out the part about making use of the "ghost from the past". Disguising themselves as Panthea using her mask and cloak, Yuko and Mo are able to scare away Rixel and Gargona.
Mo leaves the mask behind in the castle, and the group watch as the bad guys leave the area. Returning to the elf palace with the final ring, they can finally complete Ono's crown. Onchao is still worried about his father, since they still don't know exactly what happened to him, aside from Panthea having had to defeat him to take his ring at some point. Phuddle shows up to put the rings together with an overly complicated explanation for how to put them together, but Mia easily figures out which order to put the rings on Onchao's horn according to the sizes of each segment.
Mia has to return to her own world, and goes to help Mario take care of Sapphire. Renzo comments that the hedgehog they found earlier seems to have recovered, and they set it free.
