She's baaaaaack.

With two hush-hush "rehearsal" shows at the Great American Music Hall in San Francisco last night, Lauryn Hill silenced the skeptics, answered years of questions, and unveiled a reinvention of sorts.

Backed by a raucous 12-piece band, the Fugees centerpiece oozed passion and soul, showing off new material, some reimagined old hits, and an aplomb reminiscent of the late 1990s, when her Miseducation of Lauryn Hill album made her the biggest artist in the world for a time.

On this night, the frail-voiced woman whose raw emotion at her 2001 MTV Unplugged performance that caused many to worry about her state of mind, let alone her musical career, was transformed into a heat-seeking funk bomb. In an hour-plus set that didn't start until 1:15 a.m. and continued even after the venue operators had turned on the lights and cut off Hill's mic, it was as though James Brown himself had inhabited her body as she let out howls, shrieks, and fist pumps of encouragement to her band.

The band kicked off the set with an almost free jazz-style intro jam, with Hill taking the stage and almost immediately storming into a hyperspeed version of her hit "Lost Ones," rattling off telling lines like, "I was hopeless now I'm on hope road" in rapid-fire fashion.

As with almost all of the songs she performed from Miseducation, "Lost Ones" was barely recognizable from its original version, awash in a sea of massive horn breaks, funky keyboards, and full-throttle guitars. In tune with the show being dubbed a rehearsal, there was loads of vamping, with the band trying out different rhythms in the same song and Hill often catapulting into a soul-drenched vocal improv-style scat.

The vibe of the evening was clear from the start: Hill, who has often hinted at permanent retirement from popular music, has seemingly rediscovered her vigor for performing live. What isn't clear is what exactly that means: were the rehearsals for a new album? A tour? And what ever happened to the much-hyped, Verizon-sponsored Fugees reunion album and tour that came and went with the ill-received single, "Take it Easy"?

No matter. For many Fugees fans, this--an Afro-wearing Lauryn spitting rhymes and belting out songs backed by a nimble funk band--was the return of the Fu-Gee-La.

"Lost Ones" was followed by "Final Hour," featuring Hill rhyming in an intense, soulful style that was one-part rapping and one-part singing, almost like Gil Scott-Heron meets Nina Simone.

Ms. Hill--as she has asked to be called in recent years--and her band then threw the packed house a curveball, turning the deliberate beat of "Zion" into an Afro-Cuban stomper, with Hill seemingly possessed by the spirit: "My joy! My joy! My joy!"

Hill then played a couple of snippets of new songs, belting out the uplifting chorus of one, "I'm moving on!" over a thick reggae beat, then segueing into a take on her deceased father-in-law's "Iron, Lion, Zion" over an uptempo ska rhythm. (Hill has four kids with Bob Marley's son Rohan.)

Before long, the house lights were on as 2 a.m. approached. But Hill didn't even seem to notice, charging into "How Many Mics" off the Fugees' 1996 smash The Score over a beat that gave the song a massive underbelly of funk.

The crowd's roar of approval morphed into an eruption when the band darted into the first notes of "Fu-Gee-La," also from The Score. With her voice booming, Hill delivered one of the verses that first placed her among hip-hop's finest MCs: "Fake bullets can't scar me/I can smell the weak out like safari/Play you out like Atari/Sacrifice you Hari Kari/And I'm sorry/To every single rapper Dick and Harri/Saying they want to spar me/Cause how thick my repertoire/And my memoir be/Reminding me of eating Calamari/In the Kalahari/with a band of Rastafaris."

At the conclusion of "Ready or Not," the venue operators had apparently had enough and cut off Hill's mic.

But she wasn't done.

With plenty of help from eager audience members, Hill hushed the crowd to the closest thing to complete silence that 500-plus people can achieve, and then delivered an a cappella version of "I Find it Hard to Say" off the Unplugged album. It was daring, impressive, and downright moving.

As the crowd left the venue at 2:30 a.m., many couldn't help but wonder what they'd just witnessed meant. Has Hill managed to turn the raw emotion of the Unplugged show into a sound that literally takes her brand of soul-soaked, reggae-infused hip-hop back to its funk roots?

More to the point, is she back for good this time? Hill's absence from the scene has left a gaping void in urban music for an artist that can both sing like a bird and rhyme like a beast. The subject was enough to incite Talib Kweli to write a song called "Ms. Hill," in which the rapper heaps praise on Hill and asks her to get back in the music game.

It's unclear how much Hill needs music, although her boundless spirit on the stage last night indicated she does.

But this much is true: music needs Lauryn Hill.