At High Hope Dance Academy, the five teenagers train their dancing with Skyla. Suddenly, Skyla clutches her head and falls to the ground. Camille rushes to call a doctor. Whirl and Twirl begin barking loudly, indicating something wrong. Skyla has Breeze and Slam carry her to the music room. She realizes that there is something wrong in the city of Azure, part of the Sky Realm.
As the Sky Dancers enter Azure, they noticed Muddle, Jumble, and Snarl threatening a large creature resembling a manta ray. They chase the Imps off and visit the Regent of Azure, Azir. He reveals the creature was the Mermuse, a fabled creature that is said to return the rightful King of Azure. Soon, a cloaked person appears riding the Mermuse and claims to be the King. He strips his cloak and is revealed to be Sky Clone. The Azurians are forced to serve Sky Clone, and battle the Sky Dancers. The Sky Dancers are able to hold their own against the Azurians until the Mermuse defeats the heroes with its song.
The Sky Dancers are imprisoned on Azure, which Skyla is able to sense. Meanwhile, Azir laments how Sky Clone is their leader. Sky Clone appears and orders Azir to summon his troops. He plans to use the troops to conquer the Sky Realm.
The Imps taunt the Sky Dancers until the Mermuse appears and breaks them free. The Mermuse leads the Sky Dancers to the Nether Realm where they battle a Horrorcane. After escaping from the Horrorcane, they discover a female Mermuse kept prisoner by Sky Clone. They return to Azure and reveal Sky Clone's plot to Azir, who exiles Sky Clone. Queen Skyla, fully healed, appears in Azure in time for Azir to present the Sky Dancers with the Medals of the Muse. Skyla comments on how proud she is of the Sky Dancers. The Mermuses fly way, revealing a baby Mermuse.