IT SAYS SOMETHING about a documentary when you suddenly find yourself, several times, shouting "FUCK YOU" at the screen.

For me, that moment came near the end of Amy Berg's blistering and stunning West of Memphis, the most provocative retelling yet of two 20-year-old tragedies: the murders of three young boys in Arkansas and the rush to condemn, and keep locked away, the three innocent teens who rose to fame as the West Memphis Three.

Because right when everything's supposed to be golden—the teens, grown into coarsened men, have finally won their freedom—Berg drives home just how hollow some victories can be. Damien Echols, Jason Baldwin, and Jessie Misskelley Jr. could walk out of prison, professing their innocence, but only if they also agreed to plead guilty.

It's called an Alford plea. It's exceedingly rare. And it lets incompetent and malfeasant prosecutors, cops, and judges save face without ever accounting for a life-wasting mistake. Or locking up the man who actually murdered those kids.

"These three individuals pleaded guilty," some sanctimonious prosecutor clucks at a press conference, dismissing the piles of evidence turned up over the years, including new DNA. "That puts the matter to rest."

Except it doesn't. Even as West of Memphis re-examines the well-known railroading of its protagonists (a false confession from the mentally disabled Misskelley, botched forensics, and a splash of 1990s devil-worship hysteria), it pays deep respects to the pain of three families still left waiting for closure.

And there's a sharply pointed lesson buried beneath the rage: that the West Memphis Three were lucky. Eddie Vedder and Henry Rollins took up their cause. Peter Jackson (an executive producer of this film) spent part of his Lord of the Rings fortune on a defense team fit for a Wall Street CEO. Pretty good for, as Echols puts it, "poor white trash" the state wanted to throw away.

"This case is nothing out of the ordinary," Echols says from his cell. "This happens all the time."