When Harper reads one of Alex and Andre's childhood storybooks to a group of children, Andre and Alex attempt to warn her that the reader (Harper) becomes part of the story. Harper plays out Cinderella's story. However, The Four Little Pigs accidentally mashes up with Cinderella, and Justin, Andre, Max, and Zeke become the pigs, and Mason becomes the Big Bad Wolf.
The episode begins on Waverly Place where Harper is reading a storybook to a group of children when Alex pushes her away. Alex explains that it's a Wizard Storybook, a magical storybook that has the power of turning what the person reads real. Then Harper is teleported into the loft where Theresa, her evil (or "wicked" as she referred) stepmother calls her Harperella (a combination of Harper and Cinderella) and forces her to do the chores.
Then her evil stepbrothers, Justin and Max come down and give her laundry to her wash. Later Harper is washing the Waverly Substation when Alex appears, as she is Harper's fairy godmother. Alex explains to Harper that the fairy tale has to run as it's supposed to before things can go back to the way they were and then vanishes. Then Max comes in and says that the prince charming has decided to use the Substation to be the ballroom for the royal party. Harper says that she can go to the party but her stepfamily laughs at her. Back in the loft Harper summons Alex, she uses a spell to transform Harper bookdress into a princess gown and glass bowls into glass slippers. They go down (through the door) into the street and Alex turns the hot dog stand into a carriage to take Harper to the party. There she dances with prince charming, Zeke. At the stroke of midnight she goes outside leaving her glass slipper behind.
Then, to both girls' shock, Justin, Max and Zeke (with pig noses) rush inside the substation being chased by the big, bad wolf, Mason. Alex realizes that some pages are missing and Cinderella and three little pigs stories were blended together. The pig-turned boys and Harper rush into the loft being chased by Mason. While Alex finds the pages Harper has to keep Mason from eating Zeke (who built the straw house), Alex eventually finds the book pages in a drawer along with other book pages. Alex tries a page from Max's favourite magic trick book then David Copperfield comes into the room and does some magic tricks which impresses Harper. But another page that Alex tried was from Justin's science book and a caveman appeared, but the caveman has a thing for Harper. So when Harper is impressed by the magic trick he is jealous and tries to attack David Copperfield. Alex finds the right pages and the story goes back to Cinderella. Zeke Charming comes in and Theresa tries to wear the slipper but fails. Then Harper tries it and fits. She and Zeke go back to the royal party where they dance and then the story ends and the world is returned to its normality. Last but not least, Harper was back in the real world and she lived happily ever after. Finally, Alex planned that Harper and Zeke dance because they were great when they danced in romance, so they practiced but they were really bad. The ball dance is turned into a clogging dance.
- The title of the episode, Harperella, is a pun on Cinderella, which, coincidentally, is also a Disney character.
- David DeLuise, who portrays Jerry, was absent this episode.