Superior to 2003's British sleeper hit "28 Days Later" in just about every way, "28 Weeks Later" expands and develops the already-established premise of a rage-infested viral outbreak, taking it in absolutely fascinating and horrific directions that raise the stakes while making room for a provocative political subtext. Taking over the writing and directing duties for Danny Boyle is Juan Carlos Fresnadillo (2001's "Intacto"), a Spanish filmmaker making his auspicious English-language debut. He, along with co-writers Rowan Joffe and Jesus Olmos, treat the story with a disquieting real-world authenticity that doesn't pull any punches. Unlike the overrated "28 Days Later," which petered out in the third act and ended on a superficially happy note, this sequel never leavens the tension and concludes in a more haunting, open-ended way.

It has been six months since the last of the infected died off from starvation. In a first step to repair, rebuild and repopulate London, a self-contained area is being used to house survivors until the rest of the city is properly cleaned up and deemed safe for human life. It is here that Don (Robert Carlyle) is finally reunited with his children, teenager Tammy (Imogen Poots) and 12-year-old Andy (Mackintosh Muggleton), who happened to be overseas when the outbreak occurred. Their mother Alice (Catherine McCormack) was not so lucky, however, left for dead by Don when the infected attacked the country cottage they were holed up in. Just as things are starting to look up for the future, the disease rears its ugly head again after a contagious survivor is found. When orders are sent in to exterminate the population in a bid to stop the virus, Tammy and Andy, along with empathetic military doctor Scarlet (Rose Byrne) and army-soldier-with-a-conscience Doyle (Jeremy Renner), make a dangerous and daring run for safety as the approaching bombs and ravenous maniacs close in.

"28 Weeks Later" makes a single pitfall, but it is big enough to intermittently aggravate. Director Juan Carlos Fresnadillo and cinematographer Enrique Chediak (2006's "Turistas") have seen fit to shoot the action scenes in extreme shaky close-ups complete with approximately five individuals cuts per second. This ultimately renders a lot of the chaos as just that—incomprehensibly chaotic. It may positively serve to set the viewer off-balance and is sure to nauseate motion-sickness sufferers, but it also gets in the way when one isn't sure what is happening on the screen in front of him or her. This stylistic miscalculation does not ruin the film—far from it, as this is the best and most accomplished horror picture so far in 2007—but it warrants mention.

Debit notwithstanding, the blood-drenched "28 Weeks Later" is classy, intelligent and frighteningly topical. When the government sends out the order to kill all civilians as a means of wiping out every possibility for a widespread outbreak, one cannot help but ruminate about how it mirrors today's shameful, war-torn political climate, where thousands of innocent lives are used as expendable collateral in the name of selfish, single-minded motives. While technically not a zombie movie—the villains aren't the undead, but fueled by a rage-filled blood contamination—it is close enough for the comparison to be made. As such, it is the strongest entry since 2004's "Dawn of the Dead" remake.

The movie isn't strictly of the jump-out-of-your-seat variety, although there is a bit of that too, but comes from a deeper psychological place that genuinely disturbs, simmering afterwards in the viewer's memory. Furthermore, enough time is spent at the onset getting to know and care about the central characters that their fates mean much more than, say, a low-rent slasher flick. As scary and unimaginable as it may seem, "28 Weeks Later" should be celebrated for how believably thought-out and conceived the story and human figures are. At no point, really, is the audience forced to suspend disbelief, and the tactics that the government and military personnel use to solve the issue seems truthful.

Performances are exemplary. Robert Carlyle (2006's "Eragon") is a powerhouse as Don, a loving father who lies to his children about the details of their mother's death to spare himself the humiliation of revealing his own cowardice. Imogen Poots (2006's "V for Vendetta") and newcomer Mackintosh Muggleton are splendid as siblings Tammy and Andy, their tight bond in the face of an uncertain future acting as the real heart of the movie. As Scarlet and Doyle, officials willing to do what it takes to bring the kids to safety, Rose Byrne (2004's "Wicker Park") and Jeremy Renner (2005's "North Country") are almost as arresting. The lengths they go for Tammy and Andy are courageous and potentially tragic, but their choices are also clearly defined and understandable.

Emboldened with composer John Murphy's (2006's "Miami Vice") lyrically sinister original themes and heightened by better production values—the sequences of a desolate London cityscape are more comprehensive than in the original—"28 Weeks Later" is a big success. Director Juan Carlos Fresnadillo focuses in equal measures on complimenting a slam-dunk story with dimensionalized character, and uses both of these things at the service of a number of action and suspense set-pieces. One such scene, involving the infected coming into grisly contact with a helicopter blade, one-ups and puts to shame a similar scene in the recent "Grindhouse." The climax set in the dark catacombs of an abandoned football stadium—the established pick-up point—is additionally nerve-jangling, mustering up all the audience apprehension it can get out of the situation. As the heroes and victims struggle for survival in a crisis that was thought to be over, what is most unshakable in "28 Weeks Later" is the realization that the ray of hope and false sense of security they are given in the first act is not only dimmed, but completely burned out, by the film's end. "28 Days Later" had its moments, to be sure, but "28 Weeks Later" is the real deal—scarier, darker, uncompromising, and more thematically and emotionally complex.