"28 Days Later" begins with a platoon of animal rights activists barging into a British lab to free the poor primates being experimented on there.
Terrified warnings from technicians fail to stop them, and soon the chimps are on the loose, spreading the virus they've been infected with - no mere physiological agent but the sickness of raw, uncontrollable rage.
Cut to 28 days later, when the resulting epidemic has transformed almost everyone in England into a brainless zombie gripped by murderous, purposeless hate. Among the few to escape this plague are Jim and Selina, a white man and black woman who team up for mutual safety.
Joining forces with a single father and his young daughter, they're guided by a mysterious radio broadcast to an enclave of soldiers who claim to have a cure. But the motives of these military men are far from pure. They threaten to snare their female companions as sexual slaves and repopulate the world after its awful ordeal has passed.
Ads for "28 Days Later" claim it reinvents the zombie movie - a genre that's proved as unkillable as the creatures it's about, even if it doesn't stand with the most respectable forms of movie entertainment. The picture does have innovative elements. It focuses on monsters whose dehumanization has psychological as well as bodily ramifications. It confines its goriest moments to brief, hallucinatory outbursts. It's shot entirely in digital video, a cost-cutting measure that has the positive effect of lending many images the delirious overtones of a cinematic fever dream.
And it brings together two of this year's recurring movie themes: male anger, already the subject of "Hulk" and "Anger Management," and fears of new biotech developments, which are also central to "Hulk."
This said, there's much in "28 Days Later" that horror fans have seen before. Numerous plot elements recall "The Day of the Triffids" and "Night of the Living Dead." And the basic situation of survivors groping through a depopulated world is similar to Stephen King's excellent novel "The Stand" and other end-of-the-world fare, such as the '50s melodrama "The World, the Flesh, and the Devil."
What raises Danny Boyle's thriller a notch above the average is heartfelt acting, especially by Naomie Harris as the heroine and Brendan Gleeson as the single dad, and the sheer energy of Alex Garland's screenplay, which Mr. Boyle has directed with enough imagination to make his notorious "Trainspotting" seem tame by comparison. It's not a pretty picture, but it won't be soon forgotten by thriller fans with nerves and stomachs steely enough to take its violence in stride.
• Rated R; contains nudity, vulgar language, and explicit violence.