The Australian film “Somersault” is a disturbing and engrossing lesson in what happens when a young, beautiful girl puts her fate in the hands of strangers. Director Cate Shortland’s first full-length feature swept the Australian film awards in 2004, and while it occasionally seems forced, “Somersault” has enough bright moments of honesty to propel it forward.

The 16-year-old main character may look like a beautiful, fragile doll, but she has incredibly bad instincts. In a world where no one seems to have any aspirations, Heidi (Abbie Cornish) teeters between desperation and vacuity. She longs solely for the company of men and trades in the disappointing game of offering sex in return for affection.

She throws herself at every man she encounters, including the tattooed loafer her mother is dating. When her mother (Olivia Pigeot) catches the two of them together, Heidi runs off in search of a man who had come on to her at some earlier date. When Heidi gets to the man’s town and looks him up, she learns that his invitation was solely sexual – and that he is in a relationship or married. With little to no money, she decides to stay on in Jindabyne, picking up men at a local bar.

Seemingly lacking any emotional defenses, Heidi blunders through her days, yearning for companionship and a caretaker. Her naivete in affairs of the heart is often implausible and underscored by extremely immature habits: Heidi still takes comfort in a tattered, unicorn-covered notebook, be comes giddy after the purchase of new gloves, and plays patty cake with herself when walking through the woods.

This stunted adolescent is both a bane and a boon for the film. Ms. Cornish’s coltish beauty perfectly captures the crossed purposes of this character. But while her childish habits underscore the girl’s inability to subsist in an adult world, some of the character’s tics make Heidi seem mentally slow.

Then again, no one in Ms. Shortland’s Australia seems very successful at life. The other characters just manage to hide their injuries better.

When Heidi meets Joe, a charming but confused local she picks up at the bar, it seems she has found someone with a similarly passive yearning. Sam Worthington plays Joe as a warm but distant loner who refuses to take the final steps toward adulthood. Both he and Ms. Cornish make sense of a film that easily could have devolved into an exercise in narcissism.

The visual precariousness of “Somersault” matches the film’s uncertain terrain. Deeply colored accents – bleeding reds and deep blues – at times leech the pigment from the rest of the screen, as if visualizing the results of Heidi’s desperate emotional appeals.The jangling score, too, perfectly matches Heidi’s obsessive attempts to maintain the mental innocence she has physically discarded.

With each scene in “Somersault,” it is unclear if the result will be beautiful or terrible. As Heidi refuses to learn life lessons, the sense of impending doom often becomes unbearable. She seems bent on her own destruction, and while it is difficult to sympathize with Heidi’s attraction to bad decision-making, it is also hard to turn away.

mkeane@nysun.com