Rileys, the first of two movies the Twilight andNew Moon star has at Sundance, stars Stewart as a teenage prostitute and James Gandolfini as her burly protector, a grieving father who thinks he can save her in lieu of his own lost daughter.

Though she's playing young, this is no innocent story. Her character, sometimes calling herself "Mallory," sometimes "Allison," is vulgarly sexual, coming on to Gandolfini when he stops into a strip club on a business trip, though he is immediately turned off by her obvious youth and vulnerability.

Instead, he pays her to let him try to save her.

In her first scene, Stewart is wearing knee-high fishnets, a bra that isn't much of one, and a red tartan skirt as she lunges and thrusts from the stage. It may sound provocative, but her character is so obviously wounded, both emotionally and physically, judging by the many bruises on her body, that it quickly becomes awful instead of enticing.

Gandolfini wants to throw his coat over her, and the audience does, too.

However the film is received, Stewart deserves credit for taking the risk of playing this part. It's a shockingly sexual performance, but not at all "sexy." Her character's vulgar come-ons suggest someone who may have a lot of experience, but still lacks any real understanding about intimacy.

For an actress like Stewart, it would be easy to play it safe. Knock out a romantic comedy or a Nicholas Sparks weepie while the vampire cash keeps rolling in from Twilight sequels. Instead, Stewart is challenging herself, and moviegoers, too.

(AP Photo/Peter Kramer)