It's seven years in the future in the conservative suburban community of Anaheim, Calif., not far from Disneyland, and Arctor is investigating a dangerous drug called Substance D. He is observing a group of lowlife pals, including his intellectual paranoid friend James Barris (Downey), drug-addled slacker Ernie Luckman (Harrelson) and his girlfriend Donna (Ryder). They sit around a lot in a run-down tract house on a cul-de-sac where Arctor and his family once lived and are visited regularly by oddballs like Charles Freck (Cochrane), who is addicted to Substance D to such an extent that he thinks bugs are constantly creeping over him and his dog.

As Arctor observes his drug-addicted friends, he slips into taking the drugs himself. Barris observes, "There are no weekend warriors on the D. You're either on it or you haven't tried it." And so Arctor tries hiding his addiction from his boss, and he is given psychological tests at his job. Then, ironically, he gets assigned to closely watch himself, because even his immediate supervisor doesn't know his identity because of the Scramble Suit.

Meanwhile, Barris tries to double-cross Arctor by bringing in evidence to the governmental agency that shows Arctor is some kind of terrorist, but he's completely unaware that he's presenting all the evidence to Arctor, who is listening in the Scramble Suit.

Best Dick adaptation yet?

Many of the film versions of Philip K. Dick's stories are fanciful adaptations of his ideas. From Total Recall to Minority Report, Screamers to Blade Runner, the themes have always included a Big Brother world of paranoia, some suppressive totalitarian government and a technological future that squelches individuality.

A Scanner Darkly may be the most faithful adaptation of one of Dick's stories, and it doesn't change the frightening danger of drug addiction that Dick faced in reality, nor does the film try to colorize the story. In fact, the Waking Life animation that Richard Linklater perfected in 2001 seems to adapt itself well to a story where it's unclear where the lines of reality begin and end. Some of the scenes blur so close to live action that it's easy to forget the film is animated.

Despite the overall dark tone of the story, there are some funny light moments, as when Freck tries to commit suicide and goes out to buy himself a nice bottle of wine before he does. Then there's a surreal road trip with Arctor and his friends—their car breaks down and they try to remember whether or not they locked the doors before they left the house. It's a bleak cautionary tale, but sprinkled with an appropriate dose of humor.