Screenwriter Diablo Cody made her name with her very first film, “Juno.” That 2007 comedy-drama introduced a singular new voice, one that earned an Oscar for her debut screenplay. The little movie that could also got a nod for best director (Jason Reitman). The good news: Cody and Reitman have finally reunited and made another movie together. The bad news: “Young Adult” has absolutely none of the charm that made “Juno” a surprise hit.

Charlize Theron stars as Mavis, and the movie’s title describes both her career and her personality. Mavis writes a teen series much like the Sweet Valley High novels she probably read in her youth. She’s also still mired in that mind-set. She spouts adolescent cliches such as “Love conquers all.”