The title of Lynn Shelton's comedy-drama "Laggies" is never explained, but here's a guess: The term "slackers" was taken.
"Laggies" tells the story of just one laggie, Megan Burch, a peppy but highly unmotivated and irresponsible 28-year-old played with oodles of charm by Keira Knightley. Her prom was 10 years ago, but Megan is forever on summer break, still working as the sign-twirling girl for her father's accounting business (Jeff Garlin appears briefly as Ed Burch). One night, Megan reluctantly buys booze for Annika Hunter, a jaded but vulnerable teen played by Chlöe Grace Moretz. Before long, the adult and the minor are BFFs, bopping around town, going to parties and having giggly sleepovers.
Overgrown adolescents in movies are usually male, and almost always played by Seth Rogen or Jason Segel, but every now and then a woman gets to step into the role. Charlize Theron in "Young Adult" and Juliette Lewis in this year's "Kelly and Cal" are two recent examples, and both those movies covered themes of regression and misbehavior. First-time screenwriter Andrea Seigel may be treading familiar territory with "Laggies," but her characters -- and not just the female ones -- think and talk like real people. The capable cast, including Mark Webber as Megan's clueless fiancé, certainly helps.
Speaking of which, Sam Rockwell gives "Laggies" a welcome jolt of male energy as Annika's father, Craig. Though not on screen much, Rockwell sketches Craig quickly and vividly: a divorced divorce attorney, bitter but not totally humorless, a single father who refuses to play mother, too. Craig will fall for Megan, of course, but he's in no mood to feed her delusions of youth. "Wow," he says upon meeting her, "high school girls are looking rougher and rougher these days."
"Laggies" is a mainstream effort from Shelton, an otherwise resolutely indie filmmaker (her 2012 film "Your Sister's Sister" was entirely improvised). Shelton's loose, from-the-hip style and her on-location scenes in Seattle (her hometown) help make this formulaic story feel fresh.