Tris, like all other teens, must choose a faction when she's of age, then undergo rigorous testing to see if she truly belongs. Roth's premise shows keen insight into teen psychology. She's constructed her story around the idea that young people are forced to declare who they are before they know who they are. And it plays cleverly into a universal teen fear - that they might not belong anywhere.
Anyone who's watched a 16-year-old sift through college applications knows why the books have become best-sellers. Take Tris: essentially, a girl from a conservative family who chooses a party school and takes up with a hunky upperclassman.
She's raised in a pacifist faction known for their aggressively plain wardrobe, selflessness and modesty - the women are not encouraged to look in the mirror.
On the day of the Sorting Hat - whoa, wrong YA phenomenon - on the day when plain, peaceable Tris is to choose a faction, she shocks her Amish/Quaker/hippie folks (Tony Goldwyn, Ashley Judd) by choosing Dauntless, a sort of jock frat that's aggressive members train ruthlessly and graduate to police work and border patrol.
Tris is out of her element, and she's by nature not cut out for the Machiavellian back-stabbing that marks the pledge process (shades of "Ender's Game").
But she has an ally. The brooding, handsome fellow (Theo James), who supervises boot camp, takes a mysterious interest in Tris, and quietly helps her through the hazing process.
He's known only as Four, but I think most young women will agree he's a 10. He's a big asset to this narratively jumbled movie - Hollywood has a horrifyingly unerring instinct for putting androgynous dweebs in roles like this, but James, with his deep voice, five-o-clock shadow and casual authority, does strong and silent convincingly well.
The movie, for all of it's post-apocalyptic themes, is at bottom a love story, and Woodley and James are good together.
This bodes well for the movie as it evolves, as it must. "The Hunger Games" series didn't really find its feet until the second installment, and relied on Jennifer Lawrence to carry the day. This was before she was a star, though anyone who'd seen "Winter's Bone" knew she could handle it.
Woodley arrives under similar circumstances. "Can she do it" questions are asked only by those who missed "The Descendents" or "The Spectacular Now."