★ 1/2 out of four stars

It's been three summers since we first met the foursome of friends in the film version of "The Sisterhood of the Traveling Pants." The sequel finds the girls a bit older, now in college. But sadly, they're no wiser -- in fact, they seem to have regressed.

Based on Ann Brashares' series of young-adult books, the story is bound by a pair of jeans that mysteriously fit all four friends -- we're told, but never shown, that they even flatter the zaftig Carmen (America Ferrera). As in the original film, the girls keep in touch throughout their respective summer adventures by mailing the supposedly magical pants to each other. Also, the drama continues to revolve around the friends' inability to talk about their problems.

However, unlike the sparkly first film (directed by Ken Kwapis), this version (by Sanaa Hamri, better known for making music videos) socks the young women with a series of problems that may leave viewers scratching their heads.

The film certainly looks contemporary -- characters come readily equipped with cell phones and some of the friends indulge in the au courant practice of interracial dating. Why, then, doesn't Tibby (Amber Tamblyn), by now a funky, seemingly street-smart film student at NYU, seek emergency contraception the moment her boyfriend's condom breaks? And what's the deal with Carmen's disdain for e-mail?

The first installment was as watchable as any warm-hearted teen drama: Carmen was reunited with her deadbeat dad while Tibby befriended a spunky 12-year-old dying of leukemia. But the only meat to this second helping involves Bridget ("Gossip Girl" superstar Blake Lively), who continues to wrestle with her mother's suicide. Other than this, the sequel coasts on flimsy and/or benign narratives that involve postponed adulthood, cute boys who speak with deadened, unvarying inflections and ignorance of modern conveniences.