Girls swap jeans one leg at a time

Four teenage girls in a clothing store, trying on things, kidding around, giggling. Girls of four different sizes and shapes. What makes them all want to try on the same pair of pre-owned jeans? And why are the jeans a perfect fit all four times? It's the summer before the girls begin their senior year in high school, and all four have big summer plans.

Because the jeans magically fit them all, and perhaps because they all saw "Divine Secrets of the Ya-Ya Sisterhood," they come up with a plan: Each girl will wear the jeans for a week and then FedEx them to the next on the list.

Along with the solemn vow to forward the jeans on schedule comes a list of rules which must not be violated, of which the most crucial is that the girls must never let anyone else remove the jeans from their bodies. There is, however, a loophole: They can take them off themselves. Here we have a premise that could easily inspire a teenage comedy of comprehensive badness, but "The Sisterhood of the Traveling Pants" is always sweet and sometimes surprisingly touching, as the jeans accompany each girl on a key step of her journey to adulthood.

The movie, like "Mystic Pizza" (1988), assembles a group of talented young actresses who have already done good work separately and now participate in a kind of showcase. America Ferrera (whose "Real Women Have Curves" remains one of the best recent coming-of-age films) plays Carmen, who lives with her Puerto Rican mother and is thrilled to be spending the summer with her absentee non-Puerto Rican father. Alexis Bledel, who struck entirely different notes in "Sin City," is Lena, off to visit her grandparents and other relatives on a Greek island. Blake Lively plays Bridget, who attends a soccer camp in Mexico and falls in love with one of the hunky young counselors. And Amber Tamblyn (of "Joan of Arcadia") is Tibby, the one with the sardonic angle on life, who wants to be a filmmaker and takes a low-paying job for the summer at a suburban megastore where she plans to shoot a video documentary about life and work.

The stories of the four girls comes, I learn, from a novel by Ann Brashares, who has written two more in the series. The usefulness of her four-story structure is that none of the stories overstays its welcome, and the four girls aren't trapped in the same dumb suburban teenage romantic plot. They live, and they learn.

Carmen has idealized her father, Al (Bradley Whitford), even though he dumped her mother (Rachel Ticotin) years earlier. She values her Puerto Rican roots and discovers, with a shock, that her dad is planning marriage with a WASP named Lydia (Nancy Travis), who comes equipped with children and a suburban home that her father seems to desire as much as his new bride. Is he ashamed of his golden-skinned daughter whose jeans show off a healthy and rounded but technically overweight body?