Hudson plays Effie, the lead singer of the Dreams, a rising 1960s girl group from Detroit, based on the Supremes. At the movie's halfway point, she's been demoted so that Deena (Beyonce Knowles), the prettiest, lightest-skinned member of the trio -- and the one with the less powerful voice -- can get them richer and more famous faster.
Effie's climactic number is an angry cry from the heart, and her manager, Curtis (Jamie Foxx), is the man in the cross hairs. He orchestrated her demotion. Deena takes Effie's spot on stage, and in his bed.
Yet the song is as much about lust for fame as it is for a man: "And you! And you! And you! You're gonna love me." The three acts in Hudson's rendition -- tragedy, torture, triumph -- do just that, moving the audience to cheer.
While the sequence isn't imaginatively shot, edited, costumed, or staged (one descending light fixture looks like a spaceship coming to take Hudson away), for five exhausting minutes "Dreamgirls" is something to see. We almost don't need to believe in the bogus relationship between Effie and Curtis. The pain of its demise is right there in Hudson's sweaty face, mussed hair, and out stretched arms. Hunched, wrecked, she's a hot-flashing Ethel Waters.
Hudson was a finalist three seasons ago on "American Idol," and watching her here, I thought about Barbra Streisand's screen debut in "Funny Girl." Hudson isn't given nearly enough room to make the impression Streisand did, yet the movie reminds us of something that Hollywood hasn't done much since: show us that talent is beauty. But when there's no music, "Dreamgirls" is dead, and, sadly, that goes for Hudson, too.