Although the low-budget hit from director Danny Boyle ended on a note of muted hope, none of the original characters have survived for 28 Weeks Later, which picks up the localised doomsday scenario several months later.

Too efficient for its own good, the epidemic has long since extinguished itself. With no more human flesh to cannibalise, the infected have starved to death. So the quarantine has been lifted and refugees are being sent to the Isle of Dogs, a safe zone in the heart of London's financial district secured by the US military, to begin anew.

Here Dan (Robert Carlyle) is reunited with his two kids. Tammy (Imogen Poots) is a teenager with pale, wary eyes. At 12, her brother Andy (Mackintosh Muggleton) is Britain's youngest resident.

It's quiet in England now. But not for long.

With Boyle and screenwriter Alex Garland otherwise engaged on the forthcoming sci-fi epic Sunshine, sequel duties have been entrusted to Spanish filmmaker Juan Carlo Fresnadillo, whose only previous feature was the eye-catching thriller Intacto.

Fresnadillo proves a shrewd choice. 28 Weeks Later combines traditional B-movie virtues -- economy, invention, sinewy narrative spine -- with the eerily resonant spectacle of a 21st-century metropolis stripped of its citizenry. The movie provides an apocalyptic chill with images such as poison gas drifting past Westminster at dawn, or the Docklands being firebombed.

Admittedly, the film has its share of traditional B-movie detriments too: sketchy performances, implausible narrative short cuts, and only nominal emotional investment.

Even with the family fissures running through this story, Fresnadillo fails to flesh out the humanity in his characters in the way that Boyle managed. The action flows thick and fast, culminating in a genuinely scary descent into the pitch-black Underground, but at close quarters the director's reliance on a murky palette and blurrily frenetic handheld camera slips from intentionally disorienting to downright confusing.

All these problems collide in a far-fetched scene where a sentimental GI (Jeremy Renner) starts shooting his own guys to protect the children. Much more credible, unfortunately, is the way reconstruction efforts abruptly collapse as military containment degenerates into chaos.