Somewhere in England, a group of PETA-like animal rights activists break into a lab to free some chimpanzees who have been strapped down, forced to watch horrible beatings and killings on television. A scientist implores them not to let the animals free because they are infected "with rage." Twenty-eight days later, a young bicycle messenger named Jim (Cillian Murphy) wakes up from a coma in an abandoned hospital. He wanders through the detritus of civilization, collecting warm cans of Pepsi and candy bars, calling out to anyone who might hear him. The city is deserted. The first living humans he encounters quickly inform him of what happened while he was asleep: the infection, a virus that turns any primate who catches it into ravening lunatics bent on murder, spread so quickly that civilization has basically collapsed. The few people who have survived without catching the virus, which is spread by blood or saliva and induces mindless rage within 20 seconds, live off the discarded remains of commercial culture: junk food and canned goods. Jim encounters two such survivors, Selena (Naonie Harris) and Mark (Noah Huntley). They teach him some quick survival lessons, but the clear message is that everyone is in it for him or herself. As Selena says, survival is all that is left.

Jim convinces Selena and Mark to travel with him to his home to see if his family is still alive, an ill-advised trip that results in a minor tragedy and a valuable lesson about survival. Jim is not convinced, as Selena is, that living the next moment is all that remains. He wants more, perhaps because he's an optimist. Their little group grows in size with the addition of a cab driver, Frank (Brendan Gleeson) and his daughter Hannah (Megan Burns). Frank has a radio that has been picking up broadcasts from an army outpost commanded by Major West (Christopher Eccleston), and the motley band sets out for what might be the last hope at saving civilization. What they find, along the way and at their destination, is the implacable logic of a nightmare, which is what life in England has become.

The film is a happy hodge-podge of references to other horror films. This is not done as it is in some films, where borrowing means artistic bankruptcy. This borrowing is a crafty reworking of familiar themes for a new generation, without being winkingly self-referential like the Scream series and its clones. George Romero's Night of the Living Dead, Dawn of the Dead, and Day of the Dead, the most influential horror series in history, is here; the film efficiently packs the themes of the three films into its own three acts (the discovery of the zombies and their initial rampage, the satirical defense of civilization in the form of commercialism, and the final coping in a military stronghold). Other films are here, too: the dopey but fun Night of the Comet is present in two major scenes, and the hallucinogenic final scenes at the compound reminded me of Apocalypse Now.

Cinematographer Anthony Dod Mantle is an old pro with digital cameras—he did such Dogme 95 films as Mifune and The Celebration—and his work here is a good example (convincing even me) of what good filmmakers can do with digital. He uses the medium to its fullest extent, creating an almost chiaroscuro effect in some scenes, achieving a strobe-like feel for the scenes of violence, and at times recreating a Rembrandt look, most notably on the merry band's drive to Roadblock 42. At other times, though, he shows that digital can look just about as good as film, as long as you use proper lighting. It should still be an aesthetic choice, and I don't accept it in most mainstream films, but it is obvious that the filmmakers used it for reasons that were not merely financial.

So, Danny Boyle is back, after the awful The Beach. This is a fine movie, one of the best in the horror genre to come out in some time. Boyle's screenwriter, Alex Garland, wrote the novel upon which The Beach was based: looking at the difference in quality between this film and the other, I surmise that what was wrong with The Beach was not his fault. Maybe he was angry at what was done to his previous work, so he crafted an efficient, genuinely scary movie to prove that he had something to offer. This film walks a tense and effective line between horror mayhem and humanism. While the film is about the chaos that might erupt when the basic strands of civilization collapse, it is more about how people react to it, whether they can retain their humanity in the face of monsters who have lost all humanity. The macabre last act, I think, unearths Garland and Boyle's real message: without going into too much detail, I think that they argue that the true test of civilization is the lengths to which survivors will go to craft it to suit their own desires.