Will Power

There are two momentous performances in the Darwinian horror fable I Am Legend. One is by the movie's star, Will Smith — but more about him in a minute. The other is by the movie's visual effects — not the ones that bring to life a nocturnal army of shrieking, carnivorous beasties (though those are plenty impressive) but rather the ones that render a near-future New York City that has been "ground zero" for a different kind of terror attack — Mother Nature's. Three years on from a pandemic in which a cure for cancer mutates into an incurable, rabieslike plague, the island of Manhattan has regressed into a state of frontier wilderness, and the images rendered by director Francis Lawrence, cinematographer Andrew Lesnie and visual-effects supervisor Janek Sirrs have an awesome, iconic power. Deserted cars choke the bridges. Tree roots protrude through the surface of Seventh Avenue. And Times Square bustles with a new sort of tourist — herds of wild deer stampeding through, on the run from . . . something.

That something is the Infected: human plague survivors transformed by the virus into ashen predators who have laid waste the 1 percent of humanity genetically immune to infection. By night, they take to the streets, unleashing their primordial howls like bats desperate to return to hell. By day, hindered by a vampiric reaction to sunlight, they roost in the shadows, temporarily ceding control of the city to the one remaining uninfected human, scientist Robert Neville, who has lost his wife and daughter to the virus and now spends every waking hour searching for a cure.

Those, roughly, are the events of Richard Matheson's 1954 novel I Am Legend, which has been adapted (for the third time) by screenwriter Mark Protosevich (Poseidon) and revised considerably by Oscar-winner Akiva Goldsman (A Beautiful Mind). Will Smith steps into Neville's shoes, and for much of the movie, it's literally a one-man show, with Neville going through his daily routine, tearing about the empty Manhattan streets in his strategically product-placed Mustang Shelby, raiding abandoned apartments for nonperishable supplies and trapping the occasional Infected so as to have a new trial subject for his laboratory.

Smith is simply dazzling here, and for all the undeniably impressive work the actor has done on his physique for this role, what's most appealing about him is his intelligence — how he thinks his way through a role, then finds his capacity for human weakness. Watch him, especially, when he nurses his wounded canine companion and, later, when he refuses to abandon his "post" to follow fellow disease-free survivor Anna (City of God star Alice Braga) to a supposed survivor's colony in Vermont. If he just stays put in his lab, he tells her, testing one vaccine after another, he's sure he can put things right. There's a manic edge to Neville by that point, and Smith makes you feel every inch of his impotent rage. In what already has been a pretty remarkable career, it's this performance that fully affirms Smith as one of the great leading men of his generation.

If I Am Legend is less stylistically mind-blowing and intellectually ambitious than last year's yuletide dystopia, Children of Men, it's not far off. The screenplay shrewdly condenses the pre-plague backstory to brief, staccato flashbacks and manages to shift the emphasis of the novel — which was about how Neville came to be seen as a kind of monster by a new race of non-vampire mutants — without diluting its power. (Here, the crux of the narrative is a timely dialectical argument between a man, Neville, who puts his faith in science, and a somewhat fanatical woman, Anna, who puts hers in God.)

Lawrence's direction is more subdued and artful than you expect to find in a holiday blockbuster, notwithstanding a smattering of cheap-shock edits and sound effects. More often, he takes things slow and easy, staging much of the film in long, dialogue-free handheld-camera shots that use space, production design and intricately layered sound to deliver us into Neville's desolate existence.

But when the time comes for the inevitable showdowns between Neville and the Infected, Lawrence is no slouch, notably with an ingenious standoff in which a winnowing band of daylight is all that separates Neville and his pooch from almost certain doom. If I've saved mention of those scenes for last, it's only because Lawrence — like Peter Jackson and James Cameron — is among the few filmmakers who seem to understand how digital tools work best: to magnify the human dimension of a movie instead of extinguishing it.