Under the Blacklight, Rilo Kiley's 2007 major-label debut, is surely designed as the Los Angeles quartet's entry into the big leagues, the album that makes them cross over to a mass audience -- or perhaps it's just meant to make their now de facto leader, Jenny Lewis, cross over, since it plays as a sequel to her 2006 solo stab, Rabbit Fur Coat, as much as it plays as the successor to 2004's More Adventurous, putting the former child right out front, bathing in the spotlight.

If More Adventurous gave the group's game plan away in its title, so does Under the Blacklight, for if this album is anything, it's a sleazy crawl through L.A.

nightlife, teaming with sex and tattered dreams, all illuminated by a dingy black light.

So, it's a conceptual album -- which ain't the same thing as a concept album, since there is no story here to tie it together -- and to signify the sex Lewis sings about incessantly on this record, Rilo Kiley have decided to ditch most of their indie pretensions and hazy country leanings in favor of layers of ironic new wave disco and spacy flourishes pulled straight out of mid-'80s college rock.

Echoes of earlier Rilo Kiley albums (and even Rabbit Fur Coat) are still evident -- the title track is a slow country crawl at its core, the opening "Silver Lining" glides by on a subdued blue-eyed soul groove reminiscent of Cat Power's The Greatest, a move that "15" makes more explicit, while "Dreamworld" plays like an easy listening makeover of prime R.E.M. The latter is the only song here where Blake Sennett, once a co-captain with Lewis, sings lead, confirming that he's now firmly in a subservient role to his former paramour, who dominates this record the way Natalie Merchant used to rule 10,000 Maniacs, leaving the impression that the band is now merely her support group.

This may not be entirely true -- Rilo Kiley still sound like a cohesive band here; Sennett's guitar is often forceful, not meek -- but Under the Blacklight nevertheless plays like a star turn for Lewis, for better or for worse.

Better, because she reveals here that she has the charisma to be a star, leading the band through some dicey territory with her vocals, which are easily her best on record.

Worse, because she's the one that pushes the band toward sheer silliness through her carnal obsessions, which all come from the cranium, not the crotch.

Since Lewis writes about sex at a safe, studied distance -- and even if her vocals are newly throaty, she doesn't sound sexy -- the group overcompensates with stiff disco-funk since that, naturally, is music that signifies bad sex.

And there is nothing but bad sex here.

There's the tragic girl gets "money for sex" on "Close Call"; there's the implied pornography on the clenched-fist funk of "The Moneymaker"; there's the spoiled virginity of the title character on "15"; finally, there are two descents into the ridiculous with the threesome saga "Dejalo," which is topped only by the wannabe dance craze of "Smoke Detector," where Jenny takes men back to her room to smoke them in bed.

That's a lot of cheap, tawdry sex, especially since it all feels affected, not lived in, which may be why Rilo Kiley labor so hard to get this knowing new wave disco off the ground, sometimes achieving some trashy fun, other times seeming a little adrift.

After so much heavy lifting, it's not entirely a surprise that the band runs out of momentum by the end, letting Under the Blacklight peter out with "The Angels Hung Around" and "Give a Little Love," two songs that play to their former strengths and wind up being more endearing than much of the record.

But, by that point, Rilo Kiley have done what they set out to do: they've made a record that leaves their indie rock past in the dust.

This may not burn up the charts -- it quite consciously sounds more 1987 than 2007, which may keep some listeners away -- but not a note sounds like the work of a small, precious indie rock band, with the notable exception of "Dreamworld" which, of course, is Sennett's song.

The rest of Under the Blacklight feels like the Jenny Lewis show, and even if this album doesn't push Rilo Kiley to the top, it's hard to deny that it feels like the launching pad for her ascent into true stardom.