To the modern eye, the plot for the 1954 Richard Matheson novel I Am Legend might sound something like Cast Away with zombies. Truth be told, that's not a terrible premise, and Constantine director Francis Lawrence runs with it in this third film adaptation of the novel (and first to keep its title). Where he takes it may not always work, but he makes sure we enjoy the ride. Will Smith plays Robert Neville, a virologist investigating a genetically engineered cure for cancer that has gone very, very wrong. With most of the world's population wiped out and a small remnant turned into ravenous, infected carriers, Neville ekes out a lonely existence with only a dog for company in the remains of New York City, hunting, foraging, and exploring by day and shutting himself in at night. The infected, as it turns out, are vulnerable to ultraviolet light.

Through flashbacks we see how Neville came to be in this predicament, and how he dedicated himself to finding a cure. Part of that involves capturing infected humans for testing. In doing so, he incurs the wrath of one of the local CHUDs and Neville soon finds out that these creatures are not as dumb as they look. The film wrings plenty of scares out of Neville's encounters and does a good job of revealing the monsters bit by bit. By the time they're in full-on assault mode, they resemble nothing so much as zombified versions of the I, Robot androids, right down to their wall-scaling and coordinated attacks. This makes for exciting action sequences even if it dials down the horror quotient.

Smith, for his part, does a superb job of communicating the pathos and desperation of the last man on Earth. His slow disintegration into madness is subtly evoked, and in one particularly emotional scene he handles one of the most tired clichés of the zombie genre with genuine depth. The script gives him plenty of help. Screenwriters Mark Protosevich and Akiva Goldsman show plenty of restraint, teasing out the details of the virus and its outbreak over the course of the film while elegantly laying out how Neville interacts with this post-apocalyptic world in episodic vignettes.