Black Snake Moan is a tough box of goodies to unpack, rife with both pleasure and danger at every turn. It’s a steamy, blues-infused exploitive comedy, but one with Biblical undertones that send chills of cheap moralism. Rae (Christina Ricci) is a nymphomaniac whose delicious promiscuity entangles her in all sorts of backwater troubles. When Samuel L. Jackson’s God-fearing Lazarus finds her plopped on the side of the road, he chains her to his radiator, sending her down the path of righteousness. Lazarus wants to help Rae, and there’s real tenderness in their bond. But in his “healing,” there is also the movie’s befuddling message about Christian values. Do Rae’s chains symbolize a connection to a home inside her soul, or are they a chastity belt imposed upon her will? In a bawdy B-movie, writer-director Craig Brewer, who made 2005’s Hustle & Flow, means to take his characters seriously — the sneaky accomplishment of all great low culture — but his dubious moral message threatens to make them the biggest joke of all.

When the cosmos are aligned just so, Rae suffers an uncontrollable itch for cock, undergoing a wolverine-like transformation that prompts an early scene worthy of John Waters‘ crude sexual comedy: Rae’s mind floods with the sound of grasshoppers buzzing in the country grass, while her fingers hungrily inch their way toward her waistline. Ricci can pull off trashiness with the right dose of ironic wit: Rae’s a slut, but her eyes are constantly widening like a naïve baby doll’s, hinting at possible childhood traumas that brought out the whore in her. No man is safe from her grip — or as Lazarus puts it to his friend, “She’ll be on your dick faster than stink on shit.”

Rae can also radiate incredible warmth. She sings “This Little Light of Mine” about two octaves too high, a moment that endears her even though it plays for campy giggles. At this point, Lazarus has allowed Rae to believe in her own self-worth. If there’s something commendable about Black Snake Moan, it’s the heartening surprise that it finds humanity in trash, a heart in the movies’ stereotypical Dirty South. The same way Lazarus lifts up Rae with his own burdened heart following a recent divorce, Rae cradles her soon-to-be-deployed military boyfriend as he vomits during one of his regular panic attacks. Black Snake Moan, at least in some ways, asks us to embrace each other’s flaws and transgressions as the only sensible way to suffer through them. To accept Rae as a person, first you have to accept her as the cartoonishly horny girl who pounces on even the most unassuming young boy to step into her lair. It’s hard out here for a nympho.

When Rae finally settles down with her man, he gives her a gold jewelry band to wear around her waist, a clever but smug reference to the film’s previous metal chains. Rae once again feels the pangs of nympho-fever coming on, so she tightens the band. If Brewer practices humanity on the portrayal of his characters, why does he preach such a ludicrous moral resolution? He finds a cute punchline to his story but the message is muddled. Rae takes steps to heal her wounds, but it begs wondering whether they close up too tidily. The bloody-eyed nympho becomes the good Christian. If Brewer wants a “gritty South,” he’ll need to go a little grittier, and nail a little closer to reality.