If women were suddenly unable to conceive, how would the world react to the knowledge of being among the last generations that will ever exist? Would people unite as one and walk courageously into the apocalypse, or would war and destruction reign across the globe? My bet's on the latter option, which is authentically and frighteningly brought to life in "Children of Men." A thinking person's science-fiction picture without a flying car, alien or robot-gone-haywire in sight, director Alfonso Cuaron (2004's "Harry Potter and the Prisoner of Azkaban") has conceived of a brutal, uncompromising, awe-inspiringly believable vision of the future. More concerned with exploring the "what-if's" of a planet where reproduction has ended and the human population is slowly dying off than throwing a bunch of computer-generated effects in the viewers' faces, Cuaron touches upon this hot-button scenario in a realistic fashion that never strains credibility. His polished, even intellectual, work—as well as that of cinematographer Emmanuel Lubezki (2004's "Lemony Snicket's A Series of Unfortunate Events")—pay off splendidly in what is one of the year's best films.

On November 15, 2027, the population is thrown into mourning when the world's youngest living person is assassinated at the age of 18. With most cities and countries now wastelands, London is considered—just barely—the last remaining civilized place to live. Even so, terrorist attacks and mass chaos have begun to take their toll, and illegal immigrants are being imprisoned if caught. When Theo Faron (Clive Owen) is paid a visit from old flame Julian Taylor (Julianne Moore) and her posse of rights activists—a group he once belonged to—he hesitantly agrees to help them secretly transport a young pregnant girl named Kee (Claire-Hope Ashitey) across the country's hot zones in an effort to reach the Human Project, a sanctuary at sea that has agreed to come to her aid. The journey that Theo and Kee embark upon is a treacherous one that could possibly lead to their undoing if any outsiders discover she is carrying the first baby in existence in nearly two decades.

"Children of Men" is remarkable in both the ideas it presents and in the imagination brought to its filmmaking. If one were to be asked how they would react if they knew procreation had ended, some cynical people might say it wouldn't matter because they themselves would already be dead. Think about the ramifications if such a thing were actually to occur, though. Most of the population would lose their drive to do anything of so-called importance, be it in the medical field or in entertainment or science, because all of it would cease mattering to future generations that will never be. Director Alfonso Cuaron delves into this deeply provocative notion with a grim but wholly honest treatment, resisting the temptation to bring maudlin emotions into the equation. He also gets the look and feel of this future existence just right; there are definite signs that the film is set twenty-one years from now, but they come fluidly and subtly. Overall, it isn't much different, and the current upheaval and war within certain countries makes it scarily relevant, if on a far lesser scale.

From the leads to the bit players, the actors are faultless, their disquieting, at times worn, personalities further allowing the viewer to buy into a society quickly losing hope for a tomorrow. Clive Owen (2005's "Derailed") delivers an intense, captivating turn as Theo Faron, who becomes Kee's unlikely savior, but also shades his character with an effective vulnerability. He isn't an action hero—or a superhero, for that matter—but just an average guy given an extraordinary task to fulfill. As Kee, newcomer Claire Hope-Ashitey brings strength, determination and understandable fear to a young woman who refuses to see her baby fall into the wrong hands.

In smaller roles, Michael Caine (2005's "The Weather Man") is powerful as Jasper Palmer, a confidant of Theo's who has elected to live out the rest of his waning days without hesitation or a moment of grievance, and Julianne Moore (2006's "Freedomland") has some strong scenes early on as Julian Taylor, a woman who shares a tragic past with Theo but has never stopped fighting for what she believes in.

As much a character as the human actors is the point-blank brilliant camerawork from Emmanuel Lubezki. Filmed in predominantly long tracking shots that give each scene an astoundingly potent immediacy that couldn't possibly be emulated with choppy cutting, there are at least two extended sequences—one running roughly five minutes and another going as long as ten minutes without an edit—so complex and meticulously orchestrated they take your breath away. This is technical artistry of the highest order, and if Lubezki does not go on to win the Oscar for Best Cinematography, the Academy members aren't doing their jobs.

The world as depicted in "Children of Men" is one of great despair and melancholy—television ads regularly run for Quietus, a suicide medication—but it isn't without hope. At its core is a decidedly uplifting tale of the lengths people will go to survive, not only for themselves but for the future of the human race. Emotionally satisfying as well as creatively invigorating, the film also has the courage to defy expectations and play out in ways impossible to predict. "Children of Men" is a consistently tense, demanding and altogether exhilarating experience, an instant new classic of the sci-fi genre.