LAST YEAR'S box-office sensation and poster child for small-town girls with chastity issues was Juno, the pregnant wisecracker.

This year's is likely to be Bella Swan, already pop culture's most famous virgin, thanks to the phenomenally popular "Twilight" books, from which this film is adapted.

Whether she maintains that status by design or necessity is open to question. As we see in "Twilight," her choices are limited mainly by the fact that her boyfriend is a vampire.

Put another way, Bella (Kristen Stewart) does not say no. More like "whoa" when she firsts spots the entrancing Edward Cullen (Robert Pattinson) in the high school cafeteria.

Edward is the most striking member of the Cullen clan, a very pale, very standoffish group of students at the Pacific Northwest high school where bounced-around Bella has just enrolled. She's naturally intrigued and secretly thrilled when paired with Edward in biology lab, but her presence seems to unravel him and he withdraws and acts like a jerk.

It's straight from the Tiger Beat letters page: He's so handsome, so obviously into me, but so rude!

Edward hints at a dark secret, and Bella notes that the local Indians give him funny looks. She consults tomes of aboriginal legends to ferret out the awful truth, and Edward explains the relationship implications: He's a vampire, and his longing to be with her is inseparable from his longing to sink his teeth into her.

Dracula might have put it this way: I vant to suck your blood.

The movie, and the "Twilight" books, overtly conflate this urge with sexual desire, as vampire stories always have. The genius of the Twilight series is that it merges the mysterious sexuality of the vampire with teen girls' interest/anxiety about sex.

On that score, Edward has archetypal appeal. He is powerful, handsome and completely devoted, but functions as chaste protector - romance without the icky mess.

Older viewers are likely to find this comical, as when mind-reading Edward rescues Bella from a drunken band of sexual harassers, and spares her their "vile" and "disgusting" thoughts.


Vile and disgusting?

Can you give me an example?

But there is nothing to sully the purity of the Bella-Edward bond, and he finds other means to prove his epic love - first saving Bella from an out-of-control car, then interceding when an out-of-control vampire gets a whiff of Bella's irresistible blood fragrance and stalks her.

The late-game, rogue vampire plotline is meant to give "Twilight" an element of action and danger, but here the movie falls flat. It's short on creepy atmosphere (it's nothing next to "Let the Right One In"), something that might have given pouty Edward some much-needed edge.

Edward keeps insisting that he's a dangerous monster, but you never really feel that. With his foppish pompadour, he looks like lead singer for an '80s UK pop act, and feels about as threatening. It doesn't help that his wealthy, hipster vampire family lives in a posh modern home, and subsist on non-human blood.

They liken themselves to vegetarians, and I submit that if there's one thing contemporary cinema does not need, it is a vegetarian vampire.

That said, director Catherine Hardwicke ("Thirteen") gets teen-girl culture (the high school scenes are good) and other basic ingredients right. Pattinson and Stewart (she seems especially right for this role) have good chemistry, and there is real heat in their much-delayed first kiss.

Bella's ancillary relationships resonate as well. The bond that is most believable and earthy is father-daughter, with Billy Burke well cast as the decent, reticent sheriff who's out of his depth when it comes to his daughter's boy troubles. In a few brief scenes, we get why Bella both resents and needs her absent, daffy mom.

On balance, "Twilight" is an acceptable introduction to what is certain to be a profitable and long-running series, during which we might get the answers to looming questions.

Like why the privacy-loving Cullens are not home-schooled. *

Produced by Wyck Godfrey, Mark Morgan, Karen Rosenfelt, Greg Mooradian, directed by Catherine Hardwick, written by Melissa Rosenberg, Stephenie Meyer, music by Carter Burwell, distributed by Summitt Entertainment.