The creative latitude given director Clint Eastwood for "Midnight in the Garden of Good and Evil" is almost unprecedented in a studio picture.

Centered around an intriguing true story of a gay Savannah socialite who murdered his lover and set the town abuzz in gossip, "Midnight" is about characters, characters and characters.

Whole scenes, 10-minute scenes, revolve entirely around personalities and have little, if anything to do with the plot. But the personalities are so eccentric, engrossing or mysterious that these scenes are some of the best in the film and lend the plot a casual, natural continuity.

The movie's axis personality is Jim Williams (Kevin Spacey), a Savannah art collector whose private life is something the town has been whispering about for years.

Neither flaunting or concealing his sexuality, in the punctilious Southern social scene he is an enigma whose eccentricities are tolerated for the sake of his money and power. "I'm what they call nouveau riche," Williams says of his place in society. "But then, it's the riche that counts."

The book on which the film is based was written by John Berendt, a Town and Country reporter sent to cover an upper-crust Christmas party hosted by Williams, who later that night killed his lover. Sucked in by the juicy secrets the murder revealed, Berendt stayed in Savannah to write a book about the trial.

Despite the friendship he formed with Williams, Berendt was not a character in his own book, so for the film screenwriter John Lee Hancock invented a similar reporter named John Kelso (John Cusack) as the audience's surrogate observer.

In researching his manuscript and helping prepare Williams' defense, Kelso becomes deeply caught up in the fabric of Savannah life, reporting to his editor that the town is "like 'Gone With the Wind' on Mescaline."

He makes the acquaintance of every oddball in town -- including a homeless voodoo practitioner and the local drag queen, the Lady Chablis, who plays herself and is fabulously outrageous. And every character, no matter how seemingly extraneous, becomes somehow embroiled in the case.

A slowly unfolding mystery, this movie doesn't just take place in the South, it embodies the South through Eastwood's subtle direction. Paced like a humid August afternoon on a plantation patio, it is deliberate and unhurried, yet completely fascinating.

When Williams is charged with murder even though the killing looked like self defense, it takes several conversations before we fully understand why. In part this is because it is a complex question. But more broadly it's because in Savannah, that's what conversations are like.

Here is where the latitude I mentioned comes into play. Never have I seen a Hollywood script with the kind of non-essential dialogue prevalent in "Midnight," but the dialogue serves a purpose. It gives the film a fully-encompassed sense of place. Savannah is a living, breathing character in this film because the people involved are not wholly concerned with the plot.

Despite the clear culpability of Jim Williams, "Midnight" plays like a whodunit with Cusack's reporter uncovering the mystery in layers. Spacey contributes to the puzzle with a cheeky, wonderfully elusive performance that lends Williams a devil-may-care veneer, even as he wiles away the days in a jail cell awaiting trial. (Spacey may land himself another Oscar nomination.)

Eastwood confidently takes chances with the pacing courtroom scenes as well, offering attorneys' arguments unedited and playing out entire lines of questioning. In any other film, this would likely bring the plot to a stand still, but here we're ever-so-patiently hanging on every word.

Eastwood makes some other interesting choices, like the conspicuous lack of incidental music, and peppers "Midnight" with an ironic wit that enhances the film's Southern charm.

It's almost as if he's letting the audience participate in a practical joke -- making the year's most understated masterwork for the same studio that cranks out the likes of "Batman and Robin."