It is Halloween in the land of Vyond, and Ellie is throwing a Halloween party. She has invited RetroMiller, her friends Jamie, Martha, Paul, Mitchell, Keyshia, and many others. The party is going along very well until they realize that the place they are partying at is the old Color Dynamics' studios, where Barney and the backyard gang are taped, and that it’s haunted by the bear from Barney’s campfire sing-along, and the bear has kidnapped Ellie, along with her ex-boyfriend Lucas and a new troublemaker named Jiminy the ogre. It’s up to everyone at the party to save Ellie once and for all!