The Langston Fashion Plaza is a dying mall that Roger acts as caretaker for with the absence of the owner, Mr. Javitz in "You Are Here".
When Steve is dumped off so the family can work on their idea of a fish stick food truck, he is given a job by Roger, but the learn that the mall is slated for demolition. Steve and the other owners decide that the mall's survival hinges on the revival of its food court, and pitch the idea of a food truck festival based on an idea from Stan. The festival is a success, despite Steve's reservations about the continued future of the mall. Roger insists that Mr. Javitz will return, and indeed he does, as an evil spirit warlock that feeds the mall on the souls of the mall's patrons, which in turn supply's him with power. Having looked into his eyes, Roger has fallen under his spell and does his bidding.
Determined to replace Roger with Steve, he sets off in pursuit of him while Steve sets a fire and the family drives their food trucks through the wall, allowing the patrons to escape. The shop owners, having tried to run bad stores in order to keep people away, have a plan to destroy the fountain with the explosives intended to demolish the mall, but become mannequins before they can implement their plan. Roger, determined to keep his position, throws Steve into the fountain, but he is saved by Mr. Javitz who puts him under his spell until Roger pushes him into the fountain instead, destroying him.