Gossip Girl and The O.C., Josh Schwartz’s teen TV shows, are sly bait-and-switches. Both are easily marketable for their hot (-mess) fashion-plate stars, wide-eyed luxury fetishism, soapy season arcs, and savvy self-reference, but both are also old-fashioned in the primacy they put on the family. Fun Size, which Schwartz directed and produced from a screenplay by Max Werner, lacks both the glossy finish of his prime-time serials (the setting is Cleveland, the dress code is bargain-store Halloween chic) and the razor-sharpness of the dialogue. But the Schwartz touch applies: In the guise of a narrowly targeted tween flick, he has delivered a smart and emotionally satisfying slice of wish fulfillment. Played by Victoria Justice, whose coltish stature and wide-featured beauty recalls a graphic-novel rendition of Winnie Cooper, Wren is a senior with her sights set on skipping town for NYU, the alma mater of her recently deceased dad. Wren is forced to patrol her gluttonous brother Albert’s (Jackson Nicoll) night of trick-or-treating, but loses him in a haunted house; Roosevelt (Thomas Mann), a debate captain with a crush, agrees to chauffeur the search party. Cruising, bruising, first kisses, and life lessons follow. The influence of John Hughes movies is felt everywhere, and like its inspirations, Fun Size revolves around what is in essence an allegorical battle for the family’s soul: Will they stand proud as the lovable freaks that they are? The presiding spirit is that of the Beastie Boys song that plays at a crucial moment, “Fight for Your Right to Party,” a raunchy yet innocent celebration of harmless rebellion.