Welcome to a town of low-lifes and hookers where the tougher-than-nails good guys make even the meanest creations of Sly and Arnie look like damp-eyed nancy boys.
Sin City was originally built on the pages of Frank Miller's comic books - and it took a director of Robert Rodriguez's grim determination to get it onto the big screen.
Because the movie is not an adaptation but essentially a digitally animated re-creation of the comic's storyboard, Miller gets a co-credit as director (much to the dismay of the Director's Guild of America).
In reality (or as near reality you can get with film totally shot on blue screen), the collaboration is a triumph, with no compromise of Miller's gripping vision.
Rodriguez has plucked three, practically self-contained stories from Miller's catalogue and peopled them with Hollywood's A-list - in fact Josh Hartnett is on screen for a fleeting few minutes.
Everything is played out against an astonishing old Manhattan cityscape of light and shadow - a godforsaken hell hole where decent folk have long since moved away.
The best-realised yarn features Rourke as Marv, a Hellboy-type hoodlum who goes head-to-battered-head with a psycho-cannibal (played by ex-Hobbit Elijah Wood in a role an awfully long way from The Shire) after his lady gets offed.
Willis is Hartigan, a world-weary cop with a heart condition whose last job is taking out a rich kid paedophile with a dad who just happens to be a corrupt senator.
The third story is probably the weakest with Clive Owen as a grizzled gumshoe who, er, hooks up with Sin City's streetwalkers when the Mob threaten to take their territory over.
Where Sky Captain was a visual feast but a narrative famine, this is quicker to the draw by virtue of Rodriguez's skills as a storyteller and Miller's wonderfully black dialogue.
A couple of verbose thugs have "delusions of eloquence" while certain hookers are known to "work the clergy". It's best not to think too deeply about that unsaintly scenario.
Unashamedly violent and often brutally sadistic, its sordid subjects of torture, child-rape and paedophilia also see it gleefully delving into the darker corners of human nature.
So when Rodriguez loses his restraint the movie can appear exclusively pitched at those young boys (and grown men) who lock their bedroom doors for reasons other than draught exclusion.
The decision to kit legions of hookers out of a fetish magazine and arm them with a state-of-the-art arsenal also smacks of an adolescent wish-list rather than a supercool film noir.
But, these reservations aside, Rodriguez has served his inspiration well. To twist the words of Bruce's Hartigan. "There's right. There's right. And then there's this."
Tim Evans