"I WONDER where I'll be tomorrow," wonders ex-boxer Kevin Collins, who's recently escaped from a mental institution, as he wanders from town to small California town. Scruffy "Collie" scuffs along the road, trusting his future to the erstwhile kindness of strangers -- if someone's nice to him it sets the direction for his whole life.

After a dustup in a bar, Collie's picked up by Fay, an attractive alcoholic widow, who hires the punch-drunk hunk as her handyman. At Fay's rundown bungalow he's gradually drawn into her long-empty arms -- and into her scheme to kidnap and ransom a local rich kid. Haphazardly hatched by Fay and her Uncle Bud, this plot's been simmering for months; it might never have happened if catalyst Collie hadn't happened along.

In fact, just about everything's on slow boil in "After Dark, My Sweet," a neo-noir adaptation of tough-guy novelist Jim Thompson's 1955 book. Thompson's specialty is moral uncertainty, and director and co-screenwriter James Foley slowly tautens the tension and turns up the erotic heat, shading this lowlife love-crime story in vaguely depressed shades of gray and burnt-out brown.

Somewhere along the way, Collie has second thoughts about Fay and Co., and as he's hitchhiking out of town, he's picked up by a creepily sympathetic doctor, who takes a more than fatherly interest in the ex-boxer. But cushy as he has it at the manipulative doctor's, Collie's hooked and haunted by shifty-eyed Fay's bitchy charms.

Foley has brought the novel subtly up to date, and does a good job of maintaining Thompson's artful ambiguity: The novelist's characters are all suspicious of each other, and each is clearly capable of mayhem at a moment's notice. Like Thompson, Foley keeps the motivations opaque. We're kept uncertain of whom to trust, jumpy and unsettled as this weird "family" drifts toward doom.

As Fay, Rachel Ward's a picture of sulky, wasted elegance, all sharp angles and erratic, inscrutable moods. Bruce Dern offers a happily unhinged performance as the unctuously agreeable and patently untrustworthy Uncle Bud. With Dern's ex-wife and daughter starring in David Lynch's "Wild at Heart," the whole Dern family is on screen at the moment.

Jason Patric, last seen as a pretty-boy vampire in "The Lost Boys," is somewhat of a revelation here as Collie, whose violent rage lurks not too far from his ostensibly gentle surface. Beard-stubbled, his brooding blue gaze directed somewhere out there, Patric's Collie seems essentially good as he goes along with his life's aimless drift, but gravity seems intent on tugging him down to his dark side.