The most unassuming films often prove the most enjoyable. Case in point: Zero Effect, a smart, entertaining detective yarn that deftly recasts history's greatest investigative teamSherlock Holmes and Dr. Watsonas L.A. misfits. Bill Pullman and Ben Stiller play a hyper-neurotic private detective and his put-upon, poker-faced assistant, respectively, with the conceit that Pullman's sleuth is a socially inept but brilliant recluse who only feels at ease when he's on the case. Pullman is hired in absentia (he rarely leaves the house) by tycoon Ryan O'Neal to reveal the identity of a blackmailer. Of course, it's not that simple. Yet the most surprising element of Zero Effect is not the tricky plot (though there are plenty of nice twists), but Pullman's paranoid, ultimately sympathetic P.I., so detached from the world that the simple act of communication between two people becomes an oft-hilarious ordeal. The frequently ridiculous interaction between Pullman and the understandably frustrated Stiller is priceless, and Pullman's occasional words of deceptively obvious wisdom ("If you're looking for just anything, chances are you'll find something") stress the strength of first-time writer/director Jake Kasdan's script, which never seems to self-consciously strive for cleverness. Free from pretension and loose enough to let the leads explore their roles with relish, Zero Effect is a treat for those who have tired of Hollywood's typical show-offy whodunits.