Intermittently effective, improbable and finally unbelievable, David Fincher’s Panic Room is a tidy 30-minute idea encased in 100 minutes of movie. If you’ve seen the trailer, you know what the premise is. In fact, if you’ve seen the trailer, you pretty much know everything about the film except what’s hidden in the titular room — along with a handful of plot points designed to keep the story going. The problem is clearly with David Koepp’s (writer-director of Stir of Echoes) screenplay, but much of the blame must be shared by director Fincher, who, one presumes, thought himself equal to the task of overcoming the script’s limitations. He isn’t. The entire film hinges on the current phenomenon of upscale houses that boast impregnable secret rooms for the extremely paranoid very rich. Had Koepp actually crafted a script that dealt with that phenomenon or the paranoia that causes it, a very different film would likely have resulted. As it is, the movie’s largely just a claustrophobic thriller that fails just about as often as it works. Chances are it would have worked better as it was originally cast with Nicole Kidman (who had to bow out following an accident) in the Jodie Foster role. It’s not that Foster’s bad. She isn’t. She’s very good, but she’s just too take-charge to be wholly believable in what’s essentially a lady-in-distress role. With Kidman, there would have been some sense of the character evolving from that mode to one who has to find her own inner resources. With Foster, you never doubt that she can take on the three men who invade her home and hold her and her daughter (Kristen Stewart, The Safety of Objects) hostage in the house’s secret “panic room,” thereby undercutting a lot of the movie’s potential tension. As a result, the film more often succeeds on the strength of its three villains — Forest Whittaker, Dwight Yoakam, and Jared Leto — than it does on Foster’s character. And even these are far from wholly successful because they’re so clearly designed as types — and types that are utterly predictable (hands up, everyone who’s surprised that Forest Whittaker turns out to be the bad-guy-with-a-heart-of-gold). The stand-out is probably Yoakam’s Raoul. In some ways, it’s a thankless role (he spends most of the film in a ski-mask), but it’s also the most genuinely chilling performance in the film, in that the character — and the way Yoakam plays him — is so offhand and matter-of-fact in his violence. At least, that’s the case up to the point Panic Room topples over into the silliness of a Friday the 13th picture, whereupon it becomes more funny than frightening. Panic Room is by no means without its merits. Fincher and his cast do manage to generate several fairly intense suspense sequences. The problem is that they’re too few and far between to ever add up to a really cohesive whole. It’s a shame, too, based on the amount of talent involved here. Panic Room ought to have been a terrific thriller and it just isn’t.