Reviewed - Right at your door: WE ARE regularly told these days that weapons of mass destruction are cheaper and easier to obtain than ever before. Unfortunately, the same is not necessarily true of films about mass destruction.

How do you make a movie on the subject without having recourse to big-bucks special effects and other expensive paraphernalia, with all their attendant compromises?

Paul Greengrass has shown that it can be done on a (relatively) modest budget with United 93. Chris Gorak has attempted it here, but his fictional rendering of a biological attack on an American city falls well short of the visceral impact of Greengrass's docudrama.

On a normal weekday morning, unemployed musician Brad (Rory Cochrane) waves his wife Lexi (Mary McCormack) off to her job in downtown Los Angeles. A few minutes later, newsflashes report a series of explosions across the city. As the reports become increasingly scarifying, Cochrane sets out to find McCormack, but chaos on the streets and police roadblocks everywhere ultimately force him back to the house, from where he can see plumes of smoke rising above downtown.

All this - the initial shock, the unreal sense of calm at the outset, followed by rising hysteria - is well handled by Gorak, making his directorial debut after working as art director on films including Fight Club and Blade: Trinity. It's when the story returns, as, given the film's limited resources, it must, to the confines of the couple's house, that it loses its way.

With a mysterious white ash falling over the city, residents are advised to seal up their houses against possible contamination, which Cochrane, along with a neighbourhood gardener, duly does. But what happens if his wife returns? The ensuing moral dilemma seems implausible at best.

It's unclear whether Gorak wishes to explore the hard-nosed survival instinct which kicks in during such events, or the ways in which a life-and-death crisis can strip human relationships to their core, or whether his film is intended as a black satire on how you should never trust the official version of what's happening (an annoyingly glib final twist suggests the last of these). But, despite the best efforts of McCormack and Cochrane, the two-hander drama which makes up most of the film is insufficiently well-written to take the strain.