It may look like a retelling of "Cinderella", with Miku in the title role as a Cinderella-like character, but the special tells the lyrics of the song "Romeo to Cinderella"
Set in the Land of Sesame, Miku plays "CinderMiku," who lives with her step parents, her friends Rin, Prince the Dog, and the mice. CinderMiku's wish is to dance with their families' enemies' wish is to dance with their families' enemies' son of the land, but her parents lock her up.
Meanwhile, the Princess' 18th Birthday Ball becomes "Princess Charming's 18th Birthday Holiday Find-A-Husband Ball" when a minute law is brought to light, where the kingdom will be out of the royal family's rule unless she chooses a husband by the end of the night.
In the Kingdom of Sesame there is a turquoise hair colored girl named CinderMiku who lives with her stepparents, her friends, Rin, and mice. Her stepfamily have received invitations to the masquerade ball, which leaves CinderMiku tnot along to hand out with their enemy's son.
Meanwhile the King's town crier reminds King Fred the Princess Charming has until midnight to find someone to marry or lose the kingdom altogether. The King decides to invite every man and monster in the kingdom. Shortly the word is sent out around the kingdom.
The Stepmother teaches her sons a new dance in preparation for the ball. The Baker arrives as a General Invitation Deliverer and gives CinderMiku an invitation to the ball, but the Stepmother won't permit him. When the horse and carriage arrive, she locks CinderMiku and his friends up in the house. When CinderMiku wishes upon a falling star, his Fairy Godperson comes and encourages CinderElmo to come up with some plan to make his dreams come true. After CinderElmo has a wash, Fairy Godperson provides him and Zoe with smart clothes, turns the dog into a handsome prince, turns the dog bowl into a carriage and the mice into horses. CinderMiku has limited time till midnight to make the best of what Fairy Godperson granted him.
CinderElmo, Zoe and Prince make it to the ball. The Stepbrothers perform the dance their mother taught them and the Princess Charming joins them. Everyone else joins in the dance except CinderElmo who gets caught in the Herald's cloak. Princess Charming finds Prince and asks him to find CinderElmo, the only one who took her fancy. While Princess Charming turns down the marriage proposals of the Stepbrothers, CinderElmo and Zoe sneak past the Stepmother in a suit of armour to attend the last dance before midnight. The suit of armour tumbles and crashes, but Princess Charming gives CinderElmo the dance of his dreams. Before he can introduce himself, CinderElmo has seconds before the midnight deadline and runs off with his friends back home as the magic wears off, leaving only a shoe behind, but Princess Charming manages to make her choice of man to marry. Now all the royal family has to do is find the one whose foot fits the shoe in order to find the princess' beloved.
After many unsuccessful tries, the royal family head to the Stepmother's house. The shoe will not fit either of the Stepbrothers. Princess Charming recognizes CinderElmo when he comes, but CinderElmo thinks he is too young to marry. Now the King has the option to change the law that legalises a marriage between the princess and CinderElmo. The Fairy God Person changes Prince back to a dog. The royal family invites everyone to come to the palace leaving the Stepparents behind.