"Harper Knows" is the twenty-ninth episode of Wizards of Waverly Place.
The Russo family is on an assignment at PopCon, a popular comic-book and movie convention. They are on the lookout for rogue wizards who may be using their magic, and Alex is on the lookout for Harper – it's Harper's birthday, and Alex lied to get out of attending PopCon with her. Harper runs into Alex and accuses her of always lying. After a fiasco involving an enchanted costume, Alex decides it's time to tell Harper that she's a wizard.
- Lies, lies, I need a disguise – disguise as another object
Guest stars: Josh Sussman as Hugh Normous, Michael A. Shepperd as Officer Lamp, Brian Scolaro as Goblin, Lee Meriwether as Battle Diva