Skjoldbjærg's film revolved around a Swedish cop (Stellan Skarsgård) with a slightly seamy reputation who is sent to a town in northern Norway to investigate the fatal beating of a high-school girl. So far north is the town that the sun never sets in summer, and the cop's skills and mental stability are compromised by his inability to sleep in the constant daylight.
In the new Americanized version, Al Pacino takes over the lead, here renamed (in the film's most heavy-handed joke) Will Dormer. On loan from the LAPD, Dormer -- together with his partner, Hap Eckhart (Martin Donovan) -- arrives in the small town of Nightmute, Alaska, which doesn't have adequate resources or experience to investigate a mysterious killing (again of a high-school girl). Dormer is a legendary homicide detective -- so famous that green, enthusiastic local cop Ellie Burr (Hilary Swank) has studied his cases and can remember things he's said and written that Dormer himself has long forgotten.
Early in the case, a stakeout goes horribly awry: Finch, the killer (Robin Williams, not visible until more than halfway through the film), escapes, and, in a chase through the fogbound surroundings, Dormer accidentally (or maybe "accidentally on purpose") shoots and kills Hap.
Killing your own partner inadvertently would be bad enough, but the situation is even worse in this case. Dormer knows that no one will believe it was an accident because he is under investigation in a scandal back in LA and knows that Hap has cut a plea-bargain deal in return for testifying against Dormer, whose fame will make him a much gaudier feather in the internal-affairs investigators' cap. So our hero improvises a story on the spot, claiming that it was the killer who shot Hap. Of course, no one has any reason to doubt him, except one person: the killer himself, who was close enough to see what really happened. Soon enough, Finch starts pre-emptively contacting Dormer, pointing out that if he goes down, his knowledge of what really happened in the fog will take Dormer down with him.
The conflict between Dormer's dependency on, and hatred of, Finch takes a toll on his already sleep-deprived psyche as the two engage in a cat-and-mouse struggle over the physical evidence. For the first half of the movie, those who have seen the Norwegian version may be surprised at how closely both Nolan's direction and Hillary Seitz's screenplay cleave to many details of Skjoldbjærg's original. But the whole issue of the internal-affairs investigation, which gives Dormer a motive for killing Hap, is a new element -- one that completely shifts the story's moral and psychological concerns. In the first version, the cop's flaws mirror those of the killer quite precisely: He is shown to be capable of the kind of sexual impulses that led to the murder. In the new version, we see nothing of Dormer's sexual nature. In fact, the filmmakers have avoided altogether the ever-present Hollywood pressure to shoehorn in an obtrusive romantic subplot where none is needed or appropriate. Dormer's conflicts are all related to the extent to which he is the classic corrupt "good" cop -- the sort of guy who would plant evidence to insure the conviction of someone he knows is guilty.
This major plot change also allows Nolan and Seitz to beef up Williams' role and to add a lot of very clever plot reversals during the second half. The psychological fencing between cop and killer is far more interesting here than in the Norwegian film. Williams acquits himself well, but there are still problems with his casting. He is irrevocably and unforgettably hyper-funnyman Robin Williams, no matter how muted and controlled his performance. On the other hand, the film uses the baggage of his traditionally likable persona to remind us that villains are often unremarkable "nice guys" in their day-to-day lives.
Despite the conventional narrative structure, Nolan fans will recognize his style here -- the use of quick, nearly subliminal, memory flashes in the mind of a hero whose wits are frayed by physiological stresses ... the disorienting intercutting of far more extreme close-ups than usual ... and, of course, the relentless attachment to the central character's POV. What Nolan does accomplish here that we haven't seen from him before is to stage a few horrifyingly effective suspense set pieces -- one of which, in particular, is likely to stay with you for a long time.