Pullman plays Daryl Zero, a brilliant detective who commands astronomical fees but never leaves the safety of his fortified penthouse headquarters. As his exasperated assistant (Ben Stiller) explains to clients, Zero has extraordinary analytical gifts. He's also a thoughtless dweeb with frightwig hair and scarier manners. Zero is content never to face the outside world until an Oregon timber magnate (Ryan O'Neal) contracts the master sleuth to find some missing keys-a nothing task that draws Zero into the path of a mysterious, bewitching...paramedic.

That the femme fatale Gloria-a punky, vulnerable sprite played by former Nashville actress Kim Dickens-isn't the regulation pulp-fiction bombshell is only one of the neat changes wreaked on the genre by writer-director Jake Kasdan, here making his feature debut. Zero Effect is less a film-noir goof than a tip of the deerstalker to the locked-room puzzles of Arthur Conan Doyle-even if Pullman's Zero better resembles the paranoid, drug-addled Sherlock Holmes of Nicholas Meyer's revisionist novels.

Most young film-school grads making crime movies have forsaken the procedural mystery for the fatalistic cool of noir thrillers-not out of any philosophical bent, but because B-movie pulp is more of a director's medium, all lust and blood and bang! bang! cold light. (It's also easier to write and cheaper to film.) Zero Effect, on the other hand, is definitely a writer's movie. Kasdan isn't content with his cleverly constructed headscratcher of a plot; he fills the movie's downtime with scatter-gun sprays of inspiration-funny names, past exploits (e.g., the Case of the Man With Mismatched Shoelaces), the lousy rock songs Zero caterwauls in his lair. This is the first detective thriller in which the super-sleuth and his quarry size up one another over a milkshake.

As for the lead, Bill Pullman has the kind of broad, slightly bland looks that could pass for a sitcom dad's cookie-cutter cuteness. They're offset by two squinty marble eyes that can simmer with irrational perversity, but he didn't get to use them much playing dreary nice-guy also-rans in the likes of Malice and Sleepless in Seattle. But like David Lynch in the underrated Lost Highway, Jake Kasdan was sharp enough to see that Pullman is one of the only leading actors around who can look at once appealing and totally bonkers.

Pullman does a much better job of communicating genius than, say, Matt Damon, who in Good Will Hunting glibly rattles off trivia without showing a trace of obsessive temperament. Pullman's quizzical expressions and explosive zero-to-60 line readings show an eccentric but ingenious mind constantly in motion; he suggests that becoming a lonely, ill-mannered technogeek is the burden of brilliance. At the same time, he embodies the movie's deadpan absurdist tone. There's a shot of Zero in businessman disguise running alongside the timber baron on a health-club treadmill: I don't know how Pullman does it, but something about the robotic pumping of his limbs and his gung-ho sneakiness made me laugh out loud.