Adapted from Sam Shepard's play about betrayal, blackmail, and a horse racing scam that haunts its conspirators for 20 years, "Simpatico" gets by for a while on a cast full of tense, brutal, benumbed performances.

Nick Nolte stars as Vinnie, a haunted, hard-drinking and fraudulent private eye who has lived a near-destitute existence in Los Angeles for two decades on hush money extorted from a former friend named Carter (Jeff Bridges), his partner in a pony-fixing during their younger days.

As the film opens, Vinnie sets in motion a chain of events designed to see him trade places with Carter, now a rich Kentucky breeder. He plans not only on usurping the wealth his ex-buddy has amassed since their friendship disintegrated, but also on recapturing the cold heart of Rosie (Sharon Stone), the girl that came between them.

Obsessive, disheveled and unemployable, Vinnie is a vintage Nolte character -- a deeply troubled soul manifesting itself physically in worn and torn mannerisms and a face full of deep, tell-tale lines.

But looks can be deceiving, and it slowly becomes clear what a detailed scheme Vinnie is putting over. He dupes Carter into coming to L.A. then assumes his identity before smartening himself up and flying to Kentucky on his life's savings to see his plan to fruition.

Carter, in turn, seems to give up on life, taking up where Vinnie had left off by sinking into a skid row existence and crashing in a trashed SoCal trailer home.

But the revelations built on this promising set-up just don't add up to the kind of animosity-building, psyche-destroying turmoil portrayed in the powerhouse performances that drive the film.

Director Matthew Warchus, a Broadway veteran and Hollywood rookie, fails to get across that Vinnie has opened the floodgates to everything (mostly guilt) that Carter has been bottling up for 20 years.

Bridges is fine as Carter, but it's hard to buy his breakdown. This spotty adaptation (written by Warchus and David Nicholls) doesn't delve deeply enough into the character to understand the reasons behind his collapse. One can't help but wonder why he doesn't just get off his butt and jump the next plane back to Kentucky.

As the once happy and coquettish Rosie, Stone has the same problem. She gives one of the strongest performances of her career, going dumpster-diving in her darkest recesses to come up with a morose sense of humor that keeps her character -- now a rich but miserable, chain-smoking drunk -- just this side of suicide. But why has she stayed with Carter? Why was she so deeply scarred by her sexual role their decades-old scam?

The plot is built around a murky series of slowly unfurling, sepia-toned flashbacks (featuring Shawn Hatosy, Liam Waite and Kimberly Williams as the younger Nolte, Bridges and Stone). These scenes reveal how the threesome pulled off the swindle that resulted in Carter's wealth and Vinnie's downfall.

But the more that is revealed, the faster the questions pile up, and once the flashbacks have filled in some of the gaps, the key event that ruined their lives -- while traumatic perhaps -- hardly seems enough to destroy three people in the simplistic way it is portrayed.

To keep its emotional credibility, "Simpatico" needed either more turbulent complications or deeper exploration of the characters' scarred spirits. It also could have done with a dose of common sense to patch up some of its motivational shortcomings and someone to keep an eye on continuity.

How, pray tell, can it be dusk in L.A. at the same time the sun is setting in Kentucky? Stuff like that just drives me crazy.