At Enchancia Castle, Cedric is waiting outside in the courtyard. Sofia comes up to him and asks for his help with her homework: Using a spell to shrink a watermelon to the size of a grape. When she notices that he is distracted, she asks him if he is okay, to which he tells her he is not: His sister is coming to the Castle to stay for a long while. Cordelia and Calista arrive in their coach. Calista greets her uncle with affection but his sister greets him with scorn. Calista explains that the reason they are staying at Enchancia Castle so long is because their castle is being renovated and her mother and uncle grew up in Enchancia Castle back when their father was the Royal Sorceror and King Roland I was the King of Enchancia. Cedric offers to bring the bags in but Cordelia wants to do it herself. This causes a magical fight between the two.
They arrive in what will be Calista's bedroom and Cordelia uses her magic to get it ready for her daughter before leaving to get ready for dinner. Once she is gone, Cedric tells Sofia and his niece that he fears Cordelia is going to make her stay in the castle a nightmare for him since she does not think he can cast even the simplest spell before he leaves as well. Calista and Sofia are sympathetic with him and decide to tell Cordelia all the great things Cedric has done. However, when they get there, they discover that Cordelia's "hair" is really just a wig that she wears to hide a hideous green hairdo. This discovery shocks the pair to the point where they hastily leave. They run into King Roland and tell him what they saw. Roland takes the girls aside and shows them a picture of Cedric and Cordelia when they were younger. Sofia notes they were so close back then and could be again to which Roland tells her that is impossible after the incident at Cordelia's Sorceress Ball. Before he can explain, Baileywick comes over and tells him he is needed in the Throne Room to deal with the Elf Situtation again. Calista tells her they can find out what happened with her Looking Back Glass, a magic mirror they can use to see into the past.
Using the mirror, Sofia and Calista see the day of Cordelia's Sorceress Ball and see Roland, Tilly, Cedric, and Cordelia when they were kids. Cordelia is fussing over being fabulous for her Ball and Cedric is applying potion after potion to get her ready. When they are done, Cedric offers to cast a spell to make her an entrance. When Cordelia tells him he is too young to cast such a spell, he successfully casts it with a purple serum. However, when he uses the spell with a now white serum he ends up ruining Cordelia's hair. Cedric tries to fix it but he only turns it green. Cordelia's Ball is ruined and everyone blames Cedric. When they return to the present, Cedric, who saw everything, tells Sofia that this incident is why nobody, but his mother and Calista, respected or believed in him until she came along. They then head to his workshop to help Sofia with her homework.
However, when they get there, they find Cordelia rearranging all his supplies. After making her stop, Cedric tries to help Sofia with her homework but thanks to Cordelia's rearrangements he has a hard time finding his supplies. This eventually leads to another fight between them that results in the spell going wrong in a way that causes the Castle to shrink. Cedric and Cordelia keep fighting, during which a stray comment makes Sofia and Calista decide to use the Looking Back Glass again. Using the mirror, Sofia and Calista discover that the reason the serum turned white is because Cordelia knocked her hair potion into it by mistake. Upon returning to the present, Sofia and Calista use the Looking Back Glass to show Cordelia what happened to her hair was really her fault. This makes Cedric and Cordelia stop fighting and Cedric returns the Castle to normal. Roland comes in demanding an explanation and Cordelia tells him it was her fault and Cedric fixed everything. Cedric fixes his sister's beautiful hair and takes Sofia outside to help her with her homework as thanks.
- Ariel Winter as Princess Sofia
- Jess Harnell as Cedric the Sorcerer
- Jack Rainsford as Young Cedric
- Rachael MacFarlane as Cordelia the Conjuror
- Gabriella Graves as Young Cordelia
- Katie Zieff as Calista
- Travis Willingham as King Roland II/King Roland I
- Tim Gunn as Baileywick
- Bonnie Hunt as Young Tilly
- The episode's title is a play on Through the Looking Glass, the sequel to Alice in Wonderland.
- It's revealed that Tilly was once the Future Queen of Enchancia but her inheritance went to her younger brother instead.
- It is also revealed that no one has told Sofia this.
- King Roland I makes his debut appearance in this episode.
- This is the first episode with Cordelia's original hairstyle.
- Moral: Every detail is important.