Lucy: Britney Spears
Kit: Zoe Saldana
Ben: Anson Mount
Mimi: Taryn Manning
Henry: Justin Long
Lucy's dad: Dan Aykroyd
Lucy's mom: Kim Cattrall
Paramount Pictures presents a film directed by Tamra Davis. Written by Shonda Rhimes. Running time: 90 minutes. Rated PG-13 (for sexual content and brief teen drinking).

I went to "Crossroads" expecting a glitzy bimbofest and got the bimbos but not the fest. Britney Spears' feature debut is curiously low-key and even sad. Yes, it pulls itself together occasionally for a musical number, but even those are so locked into the "reality" of the story that they don't break lose into fun.

The movie opens with three eighth graders burying a box filled with symbols of their dreams of the future. Four years later, on high school graduation day, the girls are hardly on speaking terms, but they meet to dig up the box, tentatively renew their friendship, and find themselves driving to California in a convertible piloted by a hunk.

Lucy (Spears) hopes to find her long-indifferent mother in Arizona. Kit (Zoe Saldana) wants to find her fiance in Los Angeles; he has become ominously vague about wedding plans. Mimi (Taryn Manning) is pregnant, but wants to compete in a record company's open audition.

Spoiler warning! Stop reading now unless you want to learn the dismal outcome of their trip, as Lucy's mom informs her she was a "mistake," Kit's fiance turns out to have another woman and to be guilty of date-rape, and Mimi, who was the rape victim, has a miscarriage.

I'm not kidding. "Crossroads," which is being promoted with ads showing Britney bouncing on the bed while lip-synching a song, is a downer that would be even more depressing if the plot wasn't such a lame soap opera.

This is the kind of movie where the travelers stop by the roadside to yell "hello!" and keep on yelling, unaware that there is no echo. Where Britney is a virgin at 18 and enlists her lab partner to deflower her. Where when that doesn't work out, she finds herself attracted to Ben (Anson Mount), the guy who's giving them the ride, even though he is alleged to have killed a man. Where the apparent age difference between Spears and Mount makes it look like he's robbing the cradle. (In real life, he's 29, she's 20, but he's an experienced 29 and she's playing a naive 18-year-old.)

Of the three girls, Mimi has the most to do. She teaches Kit how to land a punch, tells the others why she doesn't drink, and deals almost casually with her miscarriage. Kit is a slow study who takes forever to figure out her fiance has dumped her. And Spears, as Lucy, seems to think maybe she's in a serious Winona Ryder role, but with songs.

"What are you writing in that book?" Ben asks her. "Poems," she says. He wants her to read one for him. She does. "Promise not to laugh," she says. He doesn't, but the audience does. It's the lyrics for her song "I'm Not a Girl, Not Yet a Woman." Didn't anyone warn her you can't introduce famous material as if it's new without risking a bad laugh?

Later, Ben composes music for the words, and he plays the piano while she riffs endlessly to prove she has never once thought about singing those words before.

The movie cuts away from the payoffs of the big scenes. We get the foreplay for both of Britney's sex scenes, but never see what happens. Her big meeting with her mother lacks the showdown. We can be grateful, I suppose, that after Mimi falls down some stairs after learning that Kit's fiance is the man who raped her, we are spared the details of her miscarriage and cut to her later in the hospital. Perhaps study of the live childbirth scene in the Spice Girls movie warned the filmmakers away from obstretic adventures in this one.

Like "Coyote Ugly," a movie it resembles in the wardrobe department, "Crossroads" is rated PG-13 but is going on 17. Caution, kids: It can be more dangerous to get a ride in a convertible with a cute but ominous guy than you might think. (See "Kalifornia.")

And you can't always support yourself by tips on Karaoke Night. When the girls sing in a karaoke contest, a three-gallon jug is filled with bills, which, after they're piled in stacks on the bar, are enough to pay for car repairs and the rest of the trip. Uh, huh. Curious about that karaoke bar. It has a position on the stage with an underlight and one of those poles that strippers twine around. You don't see those much in karaoke clubs.