This article is about the 2007 movie I am Legend based on the book by the same name, written by Richard Matheson. Although the creatures depicted in the outbreak are technically vampires, Matheson's original work is considered by many Science Fiction and Horror fans to be the impetus for the modern Zombie Horror genre entire, introducing many of its core themes well before Night of the Living Dead.
In a post-apocalyptic 2012, U.S. Army virologist, Lieutenant Colonel Robert Neville is left as the last healthy human in New York City and possibly the entire world. A series of flashbacks and past and recorded news programs reveal that a genetically re-engineered Measles virus created in 2008 as a cure for cancer mutated into a lethal airborne strain that spread worldwide and killed 5.4 billion people, 90% of humanity. Only 12 million possessed a natural immunity. The remaining 588 million degenerated into primal, aggressive beings referred to as "Darkseekers" (the DVD subtitles refer to them as hemocytes) who have a painful intolerance to UV radiation, forcing them to hide in buildings and other dark places during the day. The "Darkseekers" exhibit increased speed, agility, and strength. They also retain some problem-solving intelligence and the capacity to organize. The immune regular humans were hunted as prey from the infected, killed by other humans, or committed suicide.
It starts out with Neville driving in the street with a female Geman Shephard named Sam. They spot a herd of deer run in front of them. Neville and Sam go into tall grass and chase one of the deer. They manage to corner one, but a lioness comes to kill the deer. Neville is about shoot the lioness but spares it when its family arrives. Neville hears his watch beeping and see's that the sun is going down.
The next day Neville and Sam spot another deer and give chase. Sam goes on ahead while Neville jumps on top of a car and sees it escaping. He orders Sam to go after it but the deer keeps running until it passes a door in the dark. Sam goes after it but does not return. Neville goes after her but in the dark he hears a loud noise, he comes around the corner and see's blood and follows the trail upstairs and sees the deer has been killed. He flashes his light but sees a group of infected huddled together. He spots Sam under the desk but she backs off. Neville spots an infected behind him but they manage to escape.
Neville then sets a snare trap and captures an infected woman. Back in his laboratory Neville treats the infected woman without success. Later on a trip to obtain supplies he is ensnared in a trap after investigating a mannequin posed in the street and passes out. By the time he wakes up it is dusk and when he escapes the trap he falls on his knife. Neville cries in pain but decidies to leave the knife in his leg rather then pull it out as the infected will track his blood. He and Sam start sliding to the car but Sam senses the presenses of Dark Seekers and growls, Neville calls her back and she barks at the hole in the building. The Alpha male releases 3 infected dogs in the darkness. The infected dogs attack Sam and Neville. The two manage to fight them off but Sam is injured in the process.
Neville takes the wounded Sam back to his lab and administers part of the cure he was working on. Neville's attempt to cure Sam fails and she begins to turn and tries to attack while still in his arms forcing him to strangle her. Later that night, after Sam's funeral, overcome by grief he recklessly attacks a group of infected in an attempt to end his misery by killing as much as he can and in revenge for the death of his only friend.. They overwhelm Neville and nearly kill him, but he is rescued by a pair of immune survivors, Anna and a young boy named Ethan, who have traveled from Maryland after hearing one of his broadcasts. They take the injured Neville back to his home where Anna explains that they survived the outbreak aboard a Red Cross evacuation ship from São Paulo and are making their way to a putative survivors' camp in Bethel, Vermont. Anna tells Neville that she believes God has a plan for them. Neville goes into a rage and argues that there are no survivors, no God and that "everybody is dead."
Neville attempts to lower the infected woman's body temperature so the cure can take effect. That night, the Alpha Male leads a small army of infected in an attack on the house, having followed Anna and Neville back the night before. Despite heavy losses, they eventually overrun Neville's defenses. This forces Neville, Anna, and Ethan to retreat into the basement laboratory. They seal themselves in with the infected woman, where they discover that Neville's treatment is working, seconds before the remaining infected crash in the room with the Alpha male begining to smash the barrier between them. Neville realizes that her blood contains the cure and gives a vial of it to Anna, telling her that she's right and God has a plan. He pushes Anna and Ethan into an old coal chute, and then sacrifices himself to save their lives, using a hand grenade to kill himself and the attacking infected.
Anna and Ethan escape to Vermont, and locate the survivor's colony, where Anna hands over the cure. In the closing voice-over, she states that Neville's cure enabled humanity to survive and rebuild, thus establishing his legend.
The tone of the film's ending was altered before the film's release, especially the stand-off between Neville and the infected in his laboratory. Visual effects supervisor Janek Sirrs recounts the original ending starting with the stand-off: "At that point, Neville's—and the audience's—assumptions about the nature of these creatures are shown to be incorrect. We see that they have actually retained some of their humanity. There is a very important moment between the Alpha Male and Neville. The Alpha Male slapped his hand on the glass and smeared it revealing a butterfly shaped imprint." Neville realizes that the Alpha Male is identifying the infected woman he was experimenting on by a butterfly tattoo, and that the Alpha Male wants her back. Demonstrating that he will cease fighting and return her, Neville is allowed to approach them, with the Alpha Male ordering the infected not to touch him. Neville brings the Alpha Female back to consciousness, still infected due to him having removed the cure, and the Alpha Male embraces her; David Schaub stated, "Then, when Neville finally turns the Alpha Female over to the Alpha Male, there is this little love moment between the two of them." Neville and the Alpha Male then exchange stares; Neville apologizes to them, which the Alpha Male acknowledges before the infected leave. He then looks at the photos of the infected he has experimented on and killed and realizes that he is the monster of their legends; the infected think of him as someone who hunts down and kills their people. The original final shot follows Neville, Anna, and Ethan as they cross the remnants of the George Washington Bridge in hopes of finding other survivors, accompanied by a recording from Anna telling possible survivors that there is hope of a cure.