I Am Legend (film) - Plot

Plot

In September 2012, military virologist Lieutenant Colonel Robert Neville (Will Smith) is the last healthy and immune human in New York City. A genetically-engineered variant of the measles virus created by Dr. Alice Krippin (Emma Thompson), meant as a cure for cancer, had mutated into a lethal strain. It spread throughout the world, killing 90% of humanity. Most survivors became predatory, vampiric beings called "Darkseekers" that emerge after dusk to prey on those immune to the virus. In December 2009, Neville had lost his wife Zoe (Salli Richardson) and daughter Marley (Willow Smith) in a helicopter accident during a chaotic quarantine of Manhattan.

Neville's daily routine includes experimenting on infected rats to find a cure for the virus and trips through a decaying Manhattan to collect supplies or hunt for deer. He keeps vigil each day for a response to his recorded AM radio broadcasts, which instruct any survivors to meet him at midday at the South Street Seaport. Neville's isolation is broken only by the companionship of his pet German Shepherd Samantha and interaction with mannequins he has set up as patrons of a video store.

To test a treatment, Neville sets a snare trap and captures an infected woman. An enraged mutated alpha male attempts to rescue her, but is driven back by the sunlight. In the laboratory in his heavily fortified Washington Square Park home, Neville tries the new serum on the infected woman, seemingly without success.

The next day, after finding one of his mannequins moved out in the street in front of Grand Central Terminal, Neville is caught in a snare trap and passes out. He regains consciousness at dusk and frees himself, but a pack of infected dogs attack Neville and Sam. Although Neville and Sam kill the dogs, an infected dog bites Sam during the fight. Neville brings Sam home and attempts to save the dog by injecting a strain of his serum, but it is too late, as Sam starts to mutate, which then forces Neville to kill her.

Overwhelmed by grief and rage at the loss of Sam, Neville attacks a group of the infected on the seaport the following night with his SUV. He kills many, but they overwhelm and nearly kill him before he is rescued by a pair of immune humans, a woman named Anna (Alice Braga) and a boy named Ethan (Charlie Tahan), who followed his radio broadcasts from Maryland. Anna and Ethan take him back to his home. Anna explains that they are making their way to a survivors' camp in Bethel, Vermont. Neville does not believe that such a camp exists and expresses doubt when Anna says that God told her about it.

The following night, the alpha male leads an infected mob in an attack on Neville's house. Anna, who was unaware of Neville's precautions in covering his scent outside the house, inadvertently allowed the infected to follow their trail. As the infected charge the house, Neville stops the first wave with claymore mines, but finds himself defenseless against the second wave. As Neville tries to find Anna and Ethan, an infected enters and attacks him. The infected retreats upstairs and begins tearing a hole in the roof so others can get in.

After Neville saves Anna and Ethan, they retreat into the laboratory. They seal themselves in a reinforced plexiglass room with the infected woman, and discover that Neville's treatment is working; the subject looks much more human. The infected break in and the alpha male begins to throw himself against the plexiglass, cracking it. Neville then sees the butterfly tattoo on Anna and thinks of Marley who used to make a butterfly shape with her hands and then draws a vial of the infected woman's blood and gives it to Anna before shutting them inside a coal chute in the back of the lab. He detonates an M67 grenade to destroy the attackers at the cost of his own life.

Anna and Ethan arrive at the survivors' colony, where Anna hands over the antidote. Anna later states that the survivors are Neville's legacy, as his fight for a cure became legend.