
Justin embraces mortality to live with his family; his new challenge arises when Alex introduces Billie, a wizard-in-training, seeking Justin's mentorship.
On Halloween, Billie tells Roman about Pumpkin Belly, a ghoul who eats anyone whose house isn't spookily decorated; Justin, Milo and Giada defend the home from pranksters.
When Roman excels at his wizard lessons, Billie feels threatened and uses a Reverse Curse to slow him down, but it accidentally turns him into a baby.
When Billie's magic starts fizzling, she and Milo go to the wizard world for a cure; the family learns the true cause of her wonky magic: a power-draining Changeling!
When Justin forbids Billie from having a haunted house, she takes Justin to Halloween future, present and past in an attempt to help him rediscover his Halloween spirit.