The latest hellish forecast for our planet, however, makes up for the sluggishness of "Vendetta" in spades. It is "Children of Men," based on a P.D. James novel, and as directed --dazzlingly -- by Alfonso Cuaron, it is that rare futuristic thriller: grim in its scenario, yet exhilarating in its technique.

Much as director Paul Greengrass ("United 93") buoyed the second "Bourne" picture, his documentary-style strengths freeing the material from the usual thriller conventions, Cuaron gives "Children of Men" a breathless, gritty look and feel.

The showpiece sequences -- a bloody ambush on a car, or a bloody square-off between state goons and refugees -- don't scream at you with their virtuosity; they're too active and unruly to beg for audience approval. (The film may prove a tough sell.)

Still, "Children of Men" features a couple of scenes of such intricately choreographed action, sustained in shots running several minutes without a cut, you cannot quite believe what you're seeing.

The year is 2027, and it is not pretty. Mysterious environmental factors have rendered the Earth's population infertile. Great Britain is one of the few countries still functioning as a country, albeit a totalitarian one. Foreign-born citizens are being deported.

The refugee population has its defenders, however, including covert freedom fighters headed by Julian (Julianne Moore). She contacts her old lover, activist-turned-bureaucratic drone Theo (Clive Owen). A modern miracle has occurred: One of Julian's colleagues, Kee (Clare-Hope Ashitey), has conceived a child and is eight months' pregnant. She is Earth's last best hope and must be smuggled out of London to safety.

With the help of former editorial cartoonist Jasper (Michael Caine, in long silver locks), Theo and Kee run and run, and when they're not running or facing the next fearsome security checkpoint, others are running to catch up and kill them. Working from the James novel, Alfonso and his fellow screenwriters strip it down and go their own way with it.

"Children of Men" takes a while to get rolling. The early, tight-lipped scenes between Moore and Owen are fairly ordinary, and Moore's apparently immobilized forehead is proof that a good actress is not improved by a lack of expressivity.

Then comes a scene that, checking my notes, had me writing down words such as "brilliant" and "ingenious." Theo, Kee and their allies are driving down a road when their car is set upon by a rival terrorist group. The ensuing bloodshed is shocking, and nothing in the scene plays out the way you'd expect.

Cuaron and cinematographer Emmanuel Lubezki (who shot "The New World" and is a master of available light) coordinate an extraordinarily tricky action sequence using a camera that manages to cover a variety of carnage inside a speeding car, and then outside of it, and then, if memory serves, back inside. I cannot say how they did it. I can only say that I relish the chance to see it again.

Cuaron's credits include the ripping road movie "Y Tu Mama Tambien" and the best of the "Harry Potter" pictures, "The Prisoner of Azkaban." His interests here lie in painting a bleak but not absurd picture of the near future, based on terrors present. The images may sample such visual touchstones as Nazi occupations and the Abu Ghraib prison pictures, but Cuaron makes the references part of a convincing fabric.

The film doesn't go for much humour, but Caine's performance as a jolly old dope-smoking radical in hiding is plenty enjoyable. He seems like an actor reborn. Cuaron's hand-held technique favors a lot of medium and long shots at key dramatic junctures, and for an actor it's like a change of scenery. (Also, I love the way Jasper keeps calling Theo "amigo," just like Mort Mills did with Charlton Heston in "Touch of Evil.")